# Zen 5

Published articles for Zen 5.

This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles.

## ChaCha AVX-512 Optimization For Linux 7.5 Yields Up To 99% Improvement On AMD Zen 5

DevFeed: [ChaCha AVX-512 Optimization For Linux 7.5 Yields Up To 99% Improvement On AMD Zen 5](<https://devfeed.tech/articles/chacha-avx-512-optimization-for-linux-7-5-yields-up-to-99-improvement-on-amd-zen-5-123493.md>)

Original publisher: [Read original article](<https://www.phoronix.com/news/ChaCha-AVX-512-Linux-7.5>)

Author: Michael Larabel

Published: 2026-11-09T12:35:12Z

Content type: news

Language: en

Sources: [Phoronix](<https://devfeed.tech/sources/phoronix.md>)

Topics: [ChaCha](<https://devfeed.tech/topics/chacha-cipher.md>), [Linux Kernel](<https://devfeed.tech/topics/linux-kernel.md>)

Tags: [ai](<https://devfeed.tech/tags/ai.md>), [amd](<https://devfeed.tech/tags/amd.md>), [avx](<https://devfeed.tech/tags/avx.md>), [code](<https://devfeed.tech/tags/code.md>), [desktop-linux](<https://devfeed.tech/tags/desktop-linux.md>), [halo](<https://devfeed.tech/tags/halo.md>), [improvement](<https://devfeed.tech/tags/improvement.md>), [linux](<https://devfeed.tech/tags/linux.md>), [linux-benchmarking](<https://devfeed.tech/tags/linux-benchmarking.md>), [linux-hardware-benchmarks](<https://devfeed.tech/tags/linux-hardware-benchmarks.md>), [linux-hardware-reviews](<https://devfeed.tech/tags/linux-hardware-reviews.md>), [linux-how-to](<https://devfeed.tech/tags/linux-how-to.md>), [linux-performance](<https://devfeed.tech/tags/linux-performance.md>), [linux-server-benchmarks](<https://devfeed.tech/tags/linux-server-benchmarks.md>), [open-source-graphics](<https://devfeed.tech/tags/open-source-graphics.md>), [optimization](<https://devfeed.tech/tags/optimization.md>), [performance](<https://devfeed.tech/tags/performance.md>), [phoronix](<https://devfeed.tech/tags/phoronix.md>), [phoronix-test-suite](<https://devfeed.tech/tags/phoronix-test-suite.md>), [processors](<https://devfeed.tech/tags/processors.md>), [ubuntu-benchmarks](<https://devfeed.tech/tags/ubuntu-benchmarks.md>), [ubuntu-hardware](<https://devfeed.tech/tags/ubuntu-hardware.md>), [zen-5](<https://devfeed.tech/tags/zen-5.md>)

### AI overview

A new 16-block AVX-512 ChaCha function in Linux libcrypto can improve bulk encryption performance on recent processors. The existing AVX-512VL path handles up to 8 blocks using 256-bit registers; the patch adds a 512-bit path for inputs larger than 8 blocks, gated by X86_FEATURE_PREFER_YMM. The excerpt reports up to 99% improvement on AMD Zen 5 with the full 512-bit data path and up to 39% on Zen 4 using its 256-bit data path. The change is queued in Eric Biggers' libcrypto-next branch and was expected to be submitted for the Linux 7.5 merge window.

### Source excerpt

The Linux kernel's ChaCha symmetric stream cipher code has long had an AVX-512 optimized code path but it was catering to the early generations of Intel CPUs with AVX-512 (Skylake) that suffered from down-clocking under use. But now slated for arrival with Linux 7.5 is tuning the code to perform better on today's AVX-512 Intel and AMD processors that don't suffer from this limitation. In turn the ChaCha performance is as much as 99% faster with current-generation AMD Zen 5 processors...

## Beating the compiler at signed 32-bit division

DevFeed: [Beating the compiler at signed 32-bit division](<https://devfeed.tech/articles/beating-the-compiler-at-signed-32-bit-division-110587.md>)

Original publisher: [Read original article](<https://lemire.me/blog/2026/10/31/beating-the-compiler-at-signed-32-bit-division/>)

Author: Daniel Lemire

Published: 2026-10-31T13:05:35Z

Content type: article

Language: en

Sources: [Daniel Lemire](<https://devfeed.tech/sources/daniel-lemire.md>)

Topics: [performance-engineering](<https://devfeed.tech/topics/performance-engineering.md>), [Compiler](<https://devfeed.tech/topics/compiler.md>), [LLVM](<https://devfeed.tech/topics/llvm.md>), [clang](<https://devfeed.tech/topics/clang.md>), [vectorization techniques](<https://devfeed.tech/topics/vectorization-techniques.md>)

Tags: [32-bit](<https://devfeed.tech/tags/32-bit.md>), [64-bit](<https://devfeed.tech/tags/64-bit.md>), [algorithms](<https://devfeed.tech/tags/algorithms.md>), [apple](<https://devfeed.tech/tags/apple.md>), [arm](<https://devfeed.tech/tags/arm.md>), [arrow](<https://devfeed.tech/tags/arrow.md>), [autovectorization](<https://devfeed.tech/tags/autovectorization.md>), [benchmark](<https://devfeed.tech/tags/benchmark.md>), [branch](<https://devfeed.tech/tags/branch.md>), [c](<https://devfeed.tech/tags/c.md>), [clang](<https://devfeed.tech/tags/clang.md>), [code](<https://devfeed.tech/tags/code.md>), [compiler](<https://devfeed.tech/tags/compiler.md>), [compilers](<https://devfeed.tech/tags/compilers.md>), [cycles](<https://devfeed.tech/tags/cycles.md>), [gcc](<https://devfeed.tech/tags/gcc.md>), [latency](<https://devfeed.tech/tags/latency.md>), [performance](<https://devfeed.tech/tags/performance.md>), [processor](<https://devfeed.tech/tags/processor.md>), [zen-5](<https://devfeed.tech/tags/zen-5.md>)

### AI overview

A signed 32-bit division optimization can use an unsigned 33-bit reciprocal multiplier on 64-bit processors, avoiding the compiler's correction step when that multiplier does not fit a signed 32-bit value. The article gives a `div32` implementation for positive, non-power-of-two constant divisors and reports lower dependency-chain latency for divisors 7, 60, and 365; throughput gains vary by compiler and processor. For divisor 1000, where the compiler's multiplier fits signed 32 bits, the new method is slightly slower on Apple M4, so the author recommends using it only when correction is needed. For runtime divisors, a revised `fastmod` signed multiplication removes a sign-dependent branch: in the reported random-sign test it is over twice as fast as hardware division on Intel and enables partial loop vectorization on M4 when autovectorization is allowed.

### Source excerpt

Dividing integers is slow on our processors. A 32-bit division costs: processor latency throughput Emerald Rapids about 12 cycles one every 6 cycles Zen 4 9 to 12 cycles one every 6 cycles Zen 5 10 to 13 cycles one every 6 cycles Arrow Lake performance core 12 cycles one every 6 cycles Apple M4 ... Continue reading Beating the compiler at signed 32-bit division

## Linux 7.4 Fixes AMD CPU TLB Size Reporting For Zen 5 & Newer

DevFeed: [Linux 7.4 Fixes AMD CPU TLB Size Reporting For Zen 5 & Newer](<https://devfeed.tech/articles/linux-7-4-fixes-amd-cpu-tlb-size-reporting-for-zen-5-newer-97446.md>)

Original publisher: [Read original article](<https://www.phoronix.com/news/Linux-7.4-Fix-Zen-5-TLB-Size>)

Author: Michael Larabel

Published: 2026-10-23T09:47:39Z

Content type: news

Language: en

Sources: [Phoronix](<https://devfeed.tech/sources/phoronix.md>)

Topics: [Linux Kernel](<https://devfeed.tech/topics/linux-kernel.md>), [Linux](<https://devfeed.tech/topics/linux.md>)

Tags: [7-4](<https://devfeed.tech/tags/7-4.md>), [amd](<https://devfeed.tech/tags/amd.md>), [cpu](<https://devfeed.tech/tags/cpu.md>), [desktop-linux](<https://devfeed.tech/tags/desktop-linux.md>), [kernel](<https://devfeed.tech/tags/kernel.md>), [linux](<https://devfeed.tech/tags/linux.md>), [linux-7-4](<https://devfeed.tech/tags/linux-7-4.md>), [linux-benchmarking](<https://devfeed.tech/tags/linux-benchmarking.md>), [linux-hardware-benchmarks](<https://devfeed.tech/tags/linux-hardware-benchmarks.md>), [linux-hardware-reviews](<https://devfeed.tech/tags/linux-hardware-reviews.md>), [linux-how-to](<https://devfeed.tech/tags/linux-how-to.md>), [linux-performance](<https://devfeed.tech/tags/linux-performance.md>), [linux-server-benchmarks](<https://devfeed.tech/tags/linux-server-benchmarks.md>), [open-source-graphics](<https://devfeed.tech/tags/open-source-graphics.md>), [phoronix](<https://devfeed.tech/tags/phoronix.md>), [phoronix-test-suite](<https://devfeed.tech/tags/phoronix-test-suite.md>), [reporting](<https://devfeed.tech/tags/reporting.md>), [size](<https://devfeed.tech/tags/size.md>), [tlb](<https://devfeed.tech/tags/tlb.md>), [ubuntu-benchmarks](<https://devfeed.tech/tags/ubuntu-benchmarks.md>), [ubuntu-hardware](<https://devfeed.tech/tags/ubuntu-hardware.md>), [under](<https://devfeed.tech/tags/under.md>), [zen-5](<https://devfeed.tech/tags/zen-5.md>)

### AI overview

Linux 7.4 corrects under-reported TLB sizes on Zen 5 and newer AMD processors. Their TLB size reporting changed to multiples of 32, but the kernel had not adapted; the merged fix conveys the correct sizes through /proc/cpuinfo and similar interfaces. Separately, Linux 7.4 adds the RMPOPT optimization for SEV-protected confidential VMs, intended to benefit lightly loaded AMD EPYC Zen 6 servers, and a sysfs interface for reporting AMD SEV status.

### Source excerpt

As a follow-up to the article in September about a Linux patch for fixing under-reported AMD Zen 5 TLB sizes, that work is now merged for the Linux 7.4 kernel...

## AMD EPYC 8005 SKU List and Value Analysis: Mainstream Sorano's Big Stride

DevFeed: [AMD EPYC 8005 SKU List and Value Analysis: Mainstream Sorano's Big Stride](<https://devfeed.tech/articles/amd-epyc-8005-sku-list-and-value-analysis-mainstream-sorano-s-big-stride-85136.md>)

Original publisher: [Read original article](<https://www.servethehome.com/amd-epyc-8005-sku-list-and-value-analysis-mainstream-soranos-big-stride/>)

Author: Ryan Smith

Published: 2026-10-12T04:00:38Z

Content type: comparison

Language: en

Sources: [ServeTheHome](<https://devfeed.tech/sources/servethehome.md>)

Topics: [Xeon 600](<https://devfeed.tech/topics/xeon-600.md>), [finops](<https://devfeed.tech/topics/finops.md>)

Tags: [amd](<https://devfeed.tech/tags/amd.md>), [analysis](<https://devfeed.tech/tags/analysis.md>), [epyc](<https://devfeed.tech/tags/epyc.md>), [epyc-8005](<https://devfeed.tech/tags/epyc-8005.md>), [server](<https://devfeed.tech/tags/server.md>), [server-cpus](<https://devfeed.tech/tags/server-cpus.md>), [sorano](<https://devfeed.tech/tags/sorano.md>), [zen-5](<https://devfeed.tech/tags/zen-5.md>)

### AI overview

This article compares AMD EPYC 8005 Sorano server CPU options by core count, clock speed, power use, cache, memory bandwidth, and price. It identifies the 16- and 24-core models as the best value by list price per core, while noting that the best choice depends on the intended workload and optimization priorities.

### Source excerpt

Following the recent launch of AMD's EPYC 8005 Sorano server CPUs, we are taking a look at the various SKU options among chips, and what configurations offer the best value for different needs The post AMD EPYC 8005 SKU List and Value Analysis: Mainstream Sorano's Big Stride appeared first on ServeTheHome.