{"id":24068,"date":"2022-12-16T19:00:21","date_gmt":"2022-12-16T19:00:21","guid":{"rendered":"https:\/\/mailinvest.blog\/index.php\/2022\/12\/16\/some-amd-radeon-rx-7900-xtx-gpus-are-showing-wildly-fluctuating-clock-speeds-possible-early-silicon\/"},"modified":"2022-12-16T19:00:21","modified_gmt":"2022-12-16T19:00:21","slug":"some-amd-radeon-rx-7900-xtx-gpus-are-showing-wildly-fluctuating-clock-speeds-possible-early-silicon","status":"publish","type":"post","link":"https:\/\/mailinvest.blog\/index.php\/2022\/12\/16\/some-amd-radeon-rx-7900-xtx-gpus-are-showing-wildly-fluctuating-clock-speeds-possible-early-silicon\/","title":{"rendered":"Some AMD Radeon RX 7900 XTX GPUs Are Showing Wildly Fluctuating Clock Speeds, Possible Early Silicon"},"content":{"rendered":"

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AMD\u2019s long-awaited RDNA3 GPUs launched on Dec. 13, and although they didn\u2019t score a knockout victory over their rivals in early tests, they\u2019re clearly worthy competitors. Their main flaw, reviewers noted, was lackluster ray tracing performance, to the surprise of exactly nobody. But now that the dust has settled and cards are in gamers\u2019 hands, reports have surfaced online showing a variety of bizarre issues. The most troubling accuses AMD of shipping the Radeon RX 790 XTX with very early silicon with disabled shader prefetch hardware.<\/p>\n

The above is still unverified at the time of this writing, but here\u2019s what we know. The reports of weird behavior vary greatly, but the most egregious is being made by a @Kepler_L2<\/a>. They found a line in the Github submission for AMD\u2019s drivers that showed a shader prefetch is not working for \u201csome\u201d cards with the A0 revision. This applies to three chips: CHIP_GFX1100, CHIP_GFX1102, and CHIP_GFX1103. That first chip is Navi31, aka the 7900 series. The second chip is Navi33, which isn\u2019t released yet. The third chip named is for APUs based on Phoenix, according to Wccftech<\/a>. That would mean AMD fixed this issue for Navi32, aka Radeon RX 7800, etc. The A0 revision is early silicon, but according to Kepler_L2, it was shipped to consumers. Twitter users are furiously trying to figure out which cards feature this revision of silicon, and how widespread it is.<\/p>\n

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Another user named Davidbepo posted a similar situation with Navi31, where an XTX card showed two different steppings. In his tweet<\/a>, the card is shown in GPU-Z as being C8 stepping, while also using A0 silicon. That is strange, as A0 would be the first revision of the hardware; it should have advanced for the final product. It\u2019s possible AMD shipped early silicon with a broken shader prefetch in some cards. It\u2019s seemingly also not working in Nav33, the company\u2019s midrange GPUs. This isn\u2019t verified yet, either, but if it\u2019s true, AMD would need to ship new silicon to rectify it.<\/p>\n

Other reports show wildly fluctuating clock speeds. Twitter user @uzzi38<\/a> reported the XTX\u2019s clocks can fluctuate between 2.4GHz and 2.9GHz with no settings changed, which is quite a spread. They linked to Techpowerup\u2019s<\/a> efficiency benchmarks, which show an even wider level of fluctuating clock speeds. In those tests, the XTX displayed a 1GHz range of clock speeds, from 1,934MHz to 2,994MHz. Even worse, their card ran at 1.6GHz in Furmark. We\u2019re all used to GPU clocks varying according to load and temps, but that is an unprecedented range in production.<\/p>\n

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A tech YouTuber in the Netherlands named Nadalina<\/a> found similar bizarre behavior on the Asus version of the XTX. She reports she ran Call of Duty at 350fps and 2.9GHz, which ran it faster than an RTX 4090. However, an hour later it dropped to 300fps and 2.4GHz, with no changes to any settings. Her GPU also produced some serious coil whine<\/a>, but that\u2019s why we have headphones we suppose. AMD graphics chief Frank Azor tweeted<\/a> to her that the company would be in touch so they could try to figure it out, so it seems like something weird is happening. And TechPowerUp<\/a> also noted its XTX was consuming over 100W of power sitting at the desktop with a multi-monitor setup, which is just weird<\/em>.<\/p>\n

This is all a mystery that we hope AMD can add some clarity to. The A0 stepping could be fixed with a hardware refresh, but that\u2019s little consolation to current card owners. It\u2019s been reported that the shader prefetch being disabled only causes a drop in performance of five percent with RDNA2. Given how different RDNA3 is in terms of architecture, it\u2019s unknown what effect that has here. For now, we will have to wait to see if AMD chimes in.<\/p>\n

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