--- title: Qt Moves Away From Direct RDRAND/RDSEED Usage For Better... description: Qt toolkit is removing direct usage of CPU RDRAND and RDSEED instructions for random number generation, switching to OS-supplied entropy instead. Benchmarks... canonical: https://daily.dev/posts/qt-moves-away-from-direct-rdrand-rdseed-usage-for-better-performance-less-bugs-ez2ddkyks twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Qt Moves Away From Direct RDRAND/RDSEED Usage For Better Performance & Less Bugs | daily.dev og:description: Qt toolkit is removing direct usage of CPU RDRAND and RDSEED instructions for random number generation, switching to OS-supplied entropy instead. Benchmarks... og:url: https://daily.dev/posts/qt-moves-away-from-direct-rdrand-rdseed-usage-for-better-performance-less-bugs-ez2ddkyks og:image: https://api.daily.dev/og/posts/eZ2Ddkyks.png og:image:alt: Qt Moves Away From Direct RDRAND/RDSEED Usage For Better Performance & Less Bugs og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Qt Moves Away From Direct RDRAND/RDSEED Usage For Better Performance & Less Bugs **[Phoronix](https://daily.dev/sources/phoronix)** · 2 min read · 0 upvotes · 0 comments ## Summary Qt toolkit is removing direct usage of CPU RDRAND and RDSEED instructions for random number generation, switching to OS-supplied entropy instead. Benchmarks show OS-provided generators (getrandom, /dev/urandom) are significantly faster than hardware instructions—filling 1GB takes 1.5-2.6 seconds via OS methods versus 79-242 seconds using RDRAND/RDSEED. The change also eliminates Qt's need to handle broken hardware RNG implementations, particularly relevant after AMD Zen 5's RDSEED bug. QRandomGenerator will now rely on OS-specific generators without meaningful quality differences. ## Full article daily.dev links to this article rather than hosting it. 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