AMD Radeon RX 7900 XTX and XT Smart Access Memory Performance

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Conclusion

In Call of Duty Modern Warfare II at 4K the Radeon RX 7900 XTX was 9% faster with SAM ON and the Radeon RX 7900 XT was 7% faster with SAM ON. With FSR the 7900 XTX was 11% faster with SAM ON and the RX 7900 XT was also 11% faster. In 1440p the RX 7900 XTX was 15% faster with SAM ON and the RX 7900 XT was 13% faster.

In F1 2022 at 4K the RX 7900 XTX was 6% faster and the RX 7900 XT was 5% faster. With FSR the 7900 XTX was 10% faster with SAM ON and the 7900 XT was 8% faster. At 4K with Ray Tracing the 7900 XTX was 2% faster with SAM ON and the RX 7900 XT was 3% faster with SAM ON. With FSR the 7900 XTX was 6% faster with SAM ON and the RX 7900 XT was 5% faster with SAM ON. At 1440p the RX 7900 XTX was 9% faster and the RX 7900 XT was 8% faster. With Ray Tracing at 1440p the RX 7900 XTX was 5% faster with SAM ON and the RX 7900 XT was 3% faster with SAM ON.

In Dying Light 2 at 4K the RX 7900 XTX was 5% faster with SAM ON and the RX 7900 XT was 2% faster with SAM ON. With FSR2 the RX 7900 XTX 10% faster with SAM ON and the RX 7900 XT was 7% faster with SAM ON. At 4K with Ray Tracing the RX 7900 XTX was 8% faster with SAM ON and the RX 7900 XT was 2% faster with SAM ON. With FSR2 the RX 7900 XTX was 9% faster with SAM ON and the RX 7900 XT was 6% faster with SAM ON. At 1440p the RX 7900 XTX was 12% faster with SAM ON and the RX 7900 XT was 7% faster with SAM ON. At 1440p with Ray Tracing the RX 7900 XTX was 10% faster with SAM ON and the RX 7900 XT was 7% faster with SAM ON.

In Far Cry 6 at 4K the RX 7900 XTX was 5% faster with SAM ON and the RX 7900 XT was 6% faster with SAM ON. FSR was 5% faster on the RX 7900 XTX and 5% on the RX 7900 XT. At 4K with DXR the RX 7900 XTX was 3% faster with SAM ON and the RX 7900 XT was 4% faster with SAM ON. With FSR the RX 7900 XTX was 6% faster with SAM ON and RX 7900 XT was 6% faster with SAM ON. At 1440p the RX 7900 XTX the performance was the same, but the RX 7900 XT was 4% faster with SAM ON. At 1440p with DXR the RX 7900 XTX was the same and the RX 7900 XT was 5% faster with SAM ON.

In Cyberpunk 2077 at 4K the RX 7900 XTX was 3% faster with SAM ON and the RX 7900 XT was identical. With FSR2 the RX 7900 XTX was 2% faster with SAM ON and the RX 7900 XT was identical. With Ray Tracing at 4K performance was pretty much the same, just a little with FSR on the XTX. At 1440p the RX 7900 XTX was 5% faster with SAM ON and the RX 7900 XT was 5% faster as well. With Ray Tracing at 1440p the RX 7900 XTX was 3% faster with SAM ON and the RX 7900 XT was similar between the two.

In Watch Dogs Legion at 4K the RX 7900 XTX was 13% faster with AMD SAM ON, and the RX 7900 XT was 6% faster with SAM ON. At 4K with Ray Tracing the RX 7900 XTX was 11% faster with SAM ON and the RX 7900 XT was 6% faster with SAM ON. At 1440p the RX 7900 XTX was 10% faster and the RX 7900 XT was 13% faster. With Ray Tracing at 1440p the RX 7900 XTX was 15% faster with SAM ON and the RX 7900 XT was 16% faster with SAM ON. We didn’t really see any differences with Metro Exodus Enhanced.

Average Radeon RX 7900 XTX increase with SAM ON (combined results) = 8% AVG with SAM ON. Minimum 2% to Maximum 15%.

Average Radeon RX 7900 XT increase with SAM ON (combined results) = 6% AVG with SAM ON. Minimum 2% to Maximum 16%.

Final Points

In our experience, lower resolutions are affected more than higher resolutions. For example, 1440p had higher gains generally speaking compared to 4K, or Ray Tracing settings. We also saw bigger improvements when FSR was being utilized, and this makes sense because FSR is upscaling from a lower resolution. There were still performance improvements even with compute-intensive Ray Tracing, and 4K, even if not the largest, they were still present. When a game is completely compute-bound, you will probably see less, but if you aren’t, you might see a decent boost. AMD Smart Access Memory benefits will also be very game dependent, the range of performance boost will depend on the game and how well it it optimized for it.

Considering the inconsistencies between reviews that we have seen, this could be a plausible and potential reason why results differ. The differences in performance are big enough with AMD Smart Access Memory that it could change the lineup or order or percentage differences between the competition’s video cards on a graph. It could swing the Radeon RX 7900 XTX and Radeon RX 7900 XT in one direction closer or farther away from the competing video card. With some games being a 10%+ difference in performance, that is significant. It could make the video card look better, or worse, on a graph just due to this feature being enabled, turned off, or not used on an Intel platform.

As a gamer researching video card performance look closely at the test setup from benchmarks and reviews you see online, and take note of the system setups. Take note if the video cards are being tested on an Intel platform, or an AMD platform and if Resize BAR is turned ON or OFF, it makes a difference. Testing or benchmarking without Resize BAR is misleading, it doesn’t tell you the real-world gaming experience. Testing in real-world conditions is preferred, in our opinion. As such, we have been enabling Resizable BAR in all of our GPU reviews (NVIDIA and AMD) since the beginning of 2021, and we will continue to do this so that it represents real-world scenarios and is meaningful to gamers looking to purchase a video card.

A Note to my fellow reviewers: Test with Resizable BAR/AMD Smart Access Memory turned on. AMD Smart Access Memory does provide a free, platform-optimized, gameplay performance improvement on AMD GPUs when combined with AMD CPUs on the platform. It is a good idea to relate the actual gameplay experience and performance gamers will experience, i.e, real-world gaming performance. Using a 13900K is commendable for bottlenecking reasons, but you are leaving performance on the table by not using AMD Smart Access Memory on AMD GPUs. This is a simple switch, easy to turn on, and new BIOSs in motherboards are now starting to enable this feature by default, so do not turn it off. To not test with Resizable BAR/AMD SAM enabled on every GPU is misleading and irresponsible for gamers buying video cards.

To gamers: If you have a compatible AMD platform, CPU, and video card, enable Resizable BAR/AMD Smart Access Memory and Enable Above 4G Decoding on your motherboard if it is not already. It is an easy toggle, a flip of the switch to gain free performance gains with your video card. If you don’t, you are throwing away performance, leaving it on the table, for absolutely no reason. Who doesn’t want a free performance uplift with no consequences? If you are on an Intel platform, you won’t get AMD Smart Access Memory, but you can still enable Resizable BAR on them as well, so at least do that for the best possible experience. This also extends to NVIDIA GPU users, enabling Resizable BAR as well. You won’t see the performance uplift that AMD Smart Access Memory provides, but at least you will have the most potential for performance. There really is a platform advantage with AMD GPUs on AMD CPUs and platform, with AMD Smart Access Memory support. So why not use it?

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Brent Justicehttps://www.thefpsreview.com
Former managing editor of GPUs at HardOCP for 18 years, Brent Justice has been reviewing computer components since the late 90s, educated in the art and method of the computer hardware review, he brings experience, knowledge, and hands-on testing with a gamer-oriented and hardware enthusiast perspective. You can follow him on Twitter - @Brent_Justice You can sub to his YouTube channel - Justice Gaming https://www.youtube.com/c/JusticeGamingChannel You can check out his computer builds on KIT - @BrentJustice https://kit.co/BrentJustice

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