{"id":19886,"date":"2022-09-21T11:15:49","date_gmt":"2022-09-21T09:15:49","guid":{"rendered":"https:\/\/g100.us\/?p=19886"},"modified":"2022-09-21T11:19:00","modified_gmt":"2022-09-21T09:19:00","slug":"what-is-cpu-ipc","status":"publish","type":"post","link":"https:\/\/g100.us\/what-is-cpu-ipc\/","title":{"rendered":"What is a CPU's IPC? Instructions per Cycle explained"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_39 counter-hierarchy ez-toc-counter ez-toc-container-direction\">\n<p class=\"ez-toc-title\">TABLE OF CONTENTS<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-668448a9ec0f1\" class=\"cssicon\"><span style=\"display: flex;align-items: center;width: 35px;height: 30px;justify-content: center;direction:ltr;\"><svg style=\"fill: #7f11e0;color:#7f11e0\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\" \/><\/svg><svg style=\"fill: #7f11e0;color:#7f11e0\" class=\"arrow-unsorted-368013\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\" \/><\/svg><\/span><\/label><label for=\"ez-toc-cssicon-toggle-item-668448a9ec0f1\" class=\"cssiconcheckbox\">1<\/label><input type=\"checkbox\" id=\"ez-toc-cssicon-toggle-item-668448a9ec0f1\" checked><nav><ul class=\"ez-toc-list ez-toc-list-level-1 \"><li class=\"ez-toc-page-1 ez-toc-heading-level-2\"><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/g100.us\/what-is-cpu-ipc\/#What_is_IPC\" title=\"What is IPC?\">What is IPC?<\/a><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-2\"><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/g100.us\/what-is-cpu-ipc\/#Defining_IPC_Where_Does_Clock_Speed_Factor_in\" title=\"Defining IPC: Where Does Clock Speed Factor in?\">Defining IPC: Where Does Clock Speed Factor in?<\/a><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-2\"><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/g100.us\/what-is-cpu-ipc\/#FAQ\" title=\"FAQ\">FAQ<\/a><ul class=\"ez-toc-list-level-3\"><li class=\"ez-toc-heading-level-3\"><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/g100.us\/what-is-cpu-ipc\/#How_Does_IPC_Improve\" title=\"How Does IPC Improve?\">How Does IPC Improve?<\/a><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-3\"><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/g100.us\/what-is-cpu-ipc\/#Does_Higher_GHz_Mean_Faster_CPU\" title=\"Does Higher GHz Mean Faster CPU?\">Does Higher GHz Mean Faster CPU?<\/a><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-3\"><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/g100.us\/what-is-cpu-ipc\/#Can_You_Measure_the_IPC_of_a_CPU\" title=\"Can You Measure the IPC of a CPU?\">Can You Measure the IPC of a CPU?<\/a><\/li><\/ul><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-2\"><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/g100.us\/what-is-cpu-ipc\/#Over_to_You\" title=\"Over to You\">Over to You<\/a><\/li><\/ul><\/nav><\/div>\n<p>If you\u2019ve looked into CPU performance to buy your next processor, you would\u2019ve encountered the term \u201cIPC\u201d here and there.<\/p>\n<p>In fact, here\u2019s a slide from AMD\u2019s recent Ryzen 7000 series launch event that touts an IPC improvement:<\/p>\n<div id=\"attachment_19899\" style=\"width: 2560px\" class=\"wp-caption alignnone\"><noscript><img aria-describedby=\"caption-attachment-19899\" decoding=\"async\" class=\"size-full wp-image-19899\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance.jpeg\" alt=\"IPC improvements and affect on CPU performance\" width=\"2560\" height=\"720\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance.jpeg 2560w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-300x84.jpeg 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-1024x288.jpeg 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-768x216.jpeg 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-1536x432.jpeg 1536w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-2048x576.jpeg 2048w\" sizes=\"(max-width: 2560px) 100vw, 2560px\"><\/noscript><img aria-describedby=\"caption-attachment-19899\" decoding=\"async\" class=\"size-full wp-image-19899 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%202560%20720%22%3E%3C%2Fsvg%3E\" alt=\"IPC improvements and affect on CPU performance\" width=\"2560\" height=\"720\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%202560%20720%22%3E%3C%2Fsvg%3E 2560w\" sizes=\"(max-width: 2560px) 100vw, 2560px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance.jpeg 2560w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-300x84.jpeg 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-1024x288.jpeg 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-768x216.jpeg 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-1536x432.jpeg 1536w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance-2048x576.jpeg 2048w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/IPC-improvements-and-affect-on-CPU-performance.jpeg\"><p id=\"caption-attachment-19899\" class=\"wp-caption-text\">Source: <a href=\"https:\/\/wccftech.com\/amd-ryzen-7000-zen-4-cpus-official-up-to-16-cores-5-7-ghz-boost-clocks-prices-between-299-699-us-27th-september-launch\/\" target=\"_blank\" rel=\"noopener\">wccftech<\/a><\/p><\/div>\n<p>In this article, I\u2019ll explain what IPC (Instructions Per Clock \/ Cycle) is and how it affects a CPU\u2019s performance.<\/p>\n<p><strong>Unfortunately, one of the simplest ways to explain IPC is still a bit complex<\/strong>: it\u2019s the number of instructions a CPU can process within a single clock cycle.<\/p>\n<p>But if this definition doesn\u2019t mean anything to you, fret not. You\u2019re not alone.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"What_is_IPC\"><\/span>What is IPC?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><strong>Clock Cycles and Clock Speeds: Diving Headfirst into CPU Microarchitecture 101<\/strong><\/p>\n<p>So, first things first. What the heck is a clock cycle?<\/p>\n<p><noscript><img decoding=\"async\" width=\"551\" height=\"414\" class=\"wp-image-19888\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/clock-cycle-visualization.png\" alt=\"Clock cycle visualization\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/clock-cycle-visualization.png 551w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/clock-cycle-visualization-300x225.png 300w\" sizes=\"(max-width: 551px) 100vw, 551px\"><\/noscript><img decoding=\"async\" width=\"551\" height=\"414\" class=\"wp-image-19888 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20551%20414%22%3E%3C%2Fsvg%3E\" alt=\"Clock cycle visualization\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20551%20414%22%3E%3C%2Fsvg%3E 551w\" sizes=\"(max-width: 551px) 100vw, 551px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/clock-cycle-visualization.png 551w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/clock-cycle-visualization-300x225.png 300w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/clock-cycle-visualization.png\"><\/p>\n<p>Well, no. Not this.<\/p>\n<p>It\u2019s actually something like this:<\/p>\n<p><noscript><img decoding=\"async\" class=\"alignnone size-full wp-image-19898\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles.jpg\" alt=\"CPU Clock Cycles\" width=\"2048\" height=\"1080\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles.jpg 2048w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-300x158.jpg 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-1024x540.jpg 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-768x405.jpg 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-1536x810.jpg 1536w\" sizes=\"(max-width: 2048px) 100vw, 2048px\"><\/noscript><img decoding=\"async\" class=\"alignnone size-full wp-image-19898 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%202048%201080%22%3E%3C%2Fsvg%3E\" alt=\"CPU Clock Cycles\" width=\"2048\" height=\"1080\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%202048%201080%22%3E%3C%2Fsvg%3E 2048w\" sizes=\"(max-width: 2048px) 100vw, 2048px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles.jpg 2048w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-300x158.jpg 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-1024x540.jpg 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-768x405.jpg 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles-1536x810.jpg 1536w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/CPU-Clock-Cycles.jpg\"><\/p>\n<p>Well, bad jokes aside, let me explain.<\/p>\n<p>Digital circuits rely on clock signals to know when and how to execute instructions.<\/p>\n<p>This is why most electronics, including CPUs, will contain an internal oscillator (clock) to maintain a steady \u2018clock tick.\u2019 These clock signals are continuous and look like a simple square wave with a high and low state (as shown above).<\/p>\n<p>Here, one \u2018cycle\u2019 in a CPU is the time interval between two of those pulses synchronized by that internal oscillator. So, that\u2019s the time taken to go from 1 low state to high and back to low.<\/p>\n<p>And the number of these \u2018cycles\u2019 it can handle per second is what we call a processor\u2019s \u2018clock speed.\u2019<\/p>\n<p>Since a processor clock cycle and clock speed could be different for every CPU architecture, we never compare CPUs of different brands\/generations using just their clock speeds.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Defining_IPC_Where_Does_Clock_Speed_Factor_in\"><\/span>Defining IPC: Where Does Clock Speed Factor in?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>IPC becomes much easier to define now that you know what a clock cycle is.<\/p>\n<p>IPC (Instructions Per Clock) is the number of instructions a CPU can execute in a single clock cycle.<\/p>\n<p>On the other hand, the clock speed of a processor (advertised in GHz) is the number of clock cycles it can complete in one second. So, a 3GHz CPU can complete a whopping 3 billion cycles in one second!<\/p>\n<p>Even within the same brand, IPCs can vary wildly.<\/p>\n<p>Here\u2019s one example, thanks to Steve from <a href=\"https:\/\/www.techspot.com\/\" target=\"_blank\" rel=\"noopener\">Techspot<\/a>:<\/p>\n<p><noscript><img decoding=\"async\" class=\"img-with-border alignnone wp-image-19890\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20.png\" alt=\"CPU benchmark for Cinebench R20\" width=\"680\" height=\"531\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20.png 1406w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20-300x234.png 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20-1024x800.png 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20-768x600.png 768w\" sizes=\"(max-width: 680px) 100vw, 680px\"><\/noscript><img decoding=\"async\" class=\"img-with-border alignnone wp-image-19890 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20680%20531%22%3E%3C%2Fsvg%3E\" alt=\"CPU benchmark for Cinebench R20\" width=\"680\" height=\"531\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20680%20531%22%3E%3C%2Fsvg%3E 680w\" sizes=\"(max-width: 680px) 100vw, 680px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20.png 1406w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20-300x234.png 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20-1024x800.png 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20-768x600.png 768w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/cpu-benchmark-for-cinebench-r20.png\"><\/p>\n<p>Just take a look at the performance numbers when you run a Cinebench R20 single-core bench on all those CPUs.<\/p>\n<p>With all processors locked at a steady 4GHz, the only aspect that CAN vary here is the number of instructions these CPUs can handle per clock cycle (their IPC).<\/p>\n<p>You can clearly see the generational jumps in performance with each new Ryzen part.<\/p>\n<p>AMD went from a single-core score of 404 (Ryzen 7 1800X) to 517 (Ryzen 7 5800X) at the exact same 4GHz frequency!<\/p>\n<h2><span class=\"ez-toc-section\" id=\"FAQ\"><\/span>FAQ<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"How_Does_IPC_Improve\"><\/span>How Does IPC Improve?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Every CPU generation improves on the previous one (with some notable exceptions).<\/p>\n<p>Although explaining how you can improve IPC would take this article into CPU microarchitecture territory, I can give you a short overview of what\u2019s happening behind the scenes.<\/p>\n<div id=\"attachment_19900\" style=\"width: 2198px\" class=\"wp-caption alignnone\"><noscript><img aria-describedby=\"caption-attachment-19900\" decoding=\"async\" class=\"size-full wp-image-19900\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements.jpg\" alt=\"AMD Ryzen Zen 4 IPC improvements\" width=\"2198\" height=\"720\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements.jpg 2198w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-300x98.jpg 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-1024x335.jpg 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-768x252.jpg 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-1536x503.jpg 1536w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-2048x671.jpg 2048w\" sizes=\"(max-width: 2198px) 100vw, 2198px\"><\/noscript><img aria-describedby=\"caption-attachment-19900\" decoding=\"async\" class=\"size-full wp-image-19900 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%202198%20720%22%3E%3C%2Fsvg%3E\" alt=\"AMD Ryzen Zen 4 IPC improvements\" width=\"2198\" height=\"720\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%202198%20720%22%3E%3C%2Fsvg%3E 2198w\" sizes=\"(max-width: 2198px) 100vw, 2198px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements.jpg 2198w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-300x98.jpg 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-1024x335.jpg 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-768x252.jpg 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-1536x503.jpg 1536w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements-2048x671.jpg 2048w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/AMD-Ryzen-Zen-4-IPC-improvements.jpg\"><p id=\"caption-attachment-19900\" class=\"wp-caption-text\">Source: <a href=\"https:\/\/www.techspot.com\/news\/95803-amd-ryzen-7000-launch-first-impressions-performance-claims.html\" target=\"_blank\" rel=\"noopener\">Techspot<\/a><\/p><\/div>\n<p>Let\u2019s use AMD\u2019s Ryzen 7000 launch event slides again, shall we? Here\u2019s the part where Mark Papermaster, from AMD, explains how Zen 4 CPUs achieved a 13% IPC uplift over the previous generation.<\/p>\n<p><noscript><img decoding=\"async\" width=\"1887\" height=\"1124\" class=\"wp-image-19891\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc.png\" alt=\"AMD Zen 4 CPUs achieved a 13% IPC\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc.png 1887w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-300x179.png 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-1024x610.png 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-768x457.png 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-1536x915.png 1536w\" sizes=\"(max-width: 1887px) 100vw, 1887px\"><\/noscript><img decoding=\"async\" width=\"1887\" height=\"1124\" class=\"wp-image-19891 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%201887%201124%22%3E%3C%2Fsvg%3E\" alt=\"AMD Zen 4 CPUs achieved a 13% IPC\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%201887%201124%22%3E%3C%2Fsvg%3E 1887w\" sizes=\"(max-width: 1887px) 100vw, 1887px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc.png 1887w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-300x179.png 300w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-1024x610.png 1024w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-768x457.png 768w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc-1536x915.png 1536w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/amd-zen-4-cpus-achieved-a-13-ipc.png\"><\/p>\n<p>As you can see here, the IPC contributors listed on the right are some aspects of a modern CPU that can be improved to get an IPC improvement.<\/p>\n<p>Let\u2019s go over what they are, shall we?<\/p>\n<ul>\n<li>L2 Cache: A memory bank built on the CPU chip, and slower than the L1 cache. It\u2019s also called the secondary cache.<\/li>\n<li>Execution Engine: Handles integer &amp; memory operations and floating-point operations.<\/li>\n<li>Branch Prediction: It speeds up the processing of <a href=\"https:\/\/en.wikipedia.org\/wiki\/Branch_(computer_science)\" target=\"_blank\" rel=\"noopener\">branch instructions<\/a> using pipelines.<\/li>\n<li>Load\/Store: A specialized unit that\u2019s responsible for executing all load and store instructions. Here\u2019s what <a href=\"https:\/\/developer.arm.com\/documentation\/dvi0027\/b\/arm-architecture-v4t\/load-and-store-instructions#:~:text=Load%20and%20store%20single%20register,offset\" target=\"_blank\" rel=\"noopener\">load and store instructions look like on ARM<\/a>.<\/li>\n<li>Front End: Deals with in-order operations like instruction fetches and decodes.<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Does_Higher_GHz_Mean_Faster_CPU\"><\/span>Does Higher GHz Mean Faster CPU?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Only when comparing CPUs from the same brand AND same generation<\/strong>.<\/p>\n<p>Clock speeds should never be used to compare performance between 2 processors in any other scenario.<\/p>\n<p>You could very well have \u20184GHz CPUs\u2019 from a decade ago that\u2019ll be obliterated by modern \u20183GHz\u2019 CPUs.<\/p>\n<p>Here\u2019s an analogy that might help:<\/p>\n<p>Let\u2019s say two guys are each tasked with filling a large hole with gravel, and they can shovel at a constant speed of 1 dig\/second.<\/p>\n<p>Think of IPC as a shovel and the clock speed as the speed at which someone\u2019s shoveling gravel.<\/p>\n<p>If both guys use the same shovel, they\u2019ll finish their tasks at precisely the same time.<\/p>\n<p>But if you switch out one shovel for a larger one and both guys continue shoveling at identical speeds \u2013 who do you think will finish their work first? Of course, the guy with the larger shovel will finish first!<\/p>\n<p>It\u2019s the same idea with IPC and clock speeds in a CPU. It doesn\u2019t make much sense to compare only the CPU speed if their IPCs can be wildly different.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Can_You_Measure_the_IPC_of_a_CPU\"><\/span>Can You Measure the IPC of a CPU?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Short answer \u2013 Not really. <\/strong><\/p>\n<p>Since clock speeds offer a relatively easy way to put a solid number to that aspect of CPU performance, some understandably expect a similar metric for IPC too.<\/p>\n<p>Sadly, there\u2019s really no way to quantify IPC because every instruction isn\u2019t equal, and these instructions would vary by workload quite drastically.<\/p>\n<p>Even a relatively straightforward task gets broken down into machine code that your CPU can digest.<\/p>\n<p>A simple program that prints a word on the screen and adds two numbers goes from looking like this:<\/p>\n<p><noscript><img decoding=\"async\" width=\"304\" height=\"286\" class=\"wp-image-19892\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/simple-program-that-prints-a-word-on-the-screen.png\" alt=\"Simple program that prints a word on the screen\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/simple-program-that-prints-a-word-on-the-screen.png 304w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/simple-program-that-prints-a-word-on-the-screen-300x282.png 300w\" sizes=\"(max-width: 304px) 100vw, 304px\"><\/noscript><img decoding=\"async\" width=\"304\" height=\"286\" class=\"wp-image-19892 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20304%20286%22%3E%3C%2Fsvg%3E\" alt=\"Simple program that prints a word on the screen\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20304%20286%22%3E%3C%2Fsvg%3E 304w\" sizes=\"(max-width: 304px) 100vw, 304px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/simple-program-that-prints-a-word-on-the-screen.png 304w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/simple-program-that-prints-a-word-on-the-screen-300x282.png 300w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/simple-program-that-prints-a-word-on-the-screen.png\"><\/p>\n<p>To something much scarier:<\/p>\n<p><noscript><img decoding=\"async\" width=\"545\" height=\"874\" class=\"wp-image-19893\" src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/lengthy-program-that-prints-a-word-on-the-screen.png\" alt=\"Lengthy program that prints a word on the screen\" srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/lengthy-program-that-prints-a-word-on-the-screen.png 545w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/lengthy-program-that-prints-a-word-on-the-screen-187x300.png 187w\" sizes=\"(max-width: 545px) 100vw, 545px\"><\/noscript><img decoding=\"async\" width=\"545\" height=\"874\" class=\"wp-image-19893 lazyload\" src=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20545%20874%22%3E%3C%2Fsvg%3E\" alt=\"Lengthy program that prints a word on the screen\" srcset=\"data:image\/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20545%20874%22%3E%3C%2Fsvg%3E 545w\" sizes=\"(max-width: 545px) 100vw, 545px\" data-srcset=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/lengthy-program-that-prints-a-word-on-the-screen.png 545w, https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/lengthy-program-that-prints-a-word-on-the-screen-187x300.png 187w\" data-src=\"https:\/\/g100.us\/wp-content\/uploads\/media\/2022\/09\/lengthy-program-that-prints-a-word-on-the-screen.png\"><\/p>\n<p>Each of these lines above is \u2018an instruction.\u2019<\/p>\n<p>Since there are so many workloads\/applications\/processes that a desktop CPU can handle, condensing how many of these instructions they can complete in one clock cycle into a meaningful number\/metric is nearly impossible.<\/p>\n<p><strong>That said, the next best thing you can do is get a rough measure of relative IPC gains. <\/strong><\/p>\n<p>Set two CPUs to the same clock and multiplier, and run a single-core benchmark like Cinebench R20 single thread. The difference in performance you see here will be pretty close to the difference in IPC.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Over_to_You\"><\/span>Over to You<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><strong><em>Have any other questions about IPC? Feel free to ask us in the <a href=\"#comments\">comments<\/a> or our <\/em><\/strong><a href=\"https:\/\/g100.us\/forum\/\"><strong><em>forum<\/em><\/strong><\/a><strong><em>!<\/em><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>If you\u2019ve looked into CPU performance to buy your next processor, you would\u2019ve encountered the term \u201cIPC\u201d here and there. In fact, here\u2019s a slide from AMD\u2019s recent Ryzen 7000 series launch event that touts an IPC improvement: In this article, I\u2019ll explain what IPC (Instructions Per Clock \/ Cycle) is and how it affects...<\/p>\n","protected":false},"author":2334,"featured_media":19894,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[74],"tags":[117],"acf":[],"_links":{"self":[{"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/posts\/19886"}],"collection":[{"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/users\/2334"}],"replies":[{"embeddable":true,"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/comments?post=19886"}],"version-history":[{"count":9,"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/posts\/19886\/revisions"}],"predecessor-version":[{"id":19912,"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/posts\/19886\/revisions\/19912"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/media\/19894"}],"wp:attachment":[{"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/media?parent=19886"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/categories?post=19886"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/g100.us\/wp-json\/wp\/v2\/tags?post=19886"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}