We previously reported on a rumor suggesting that AMD’s new Smart Access Memory (SAM) feature would only work with Ryzen 5000 Series processors due to the way older chips handled a particular instruction (PDEP), but it turns out that isn’t the case at all. Following an official response from AMD confirming that SAM doesn’t depend on PDED, an ASUS B450-PLUS motherboard user has discovered that the feature can be enabled with an AMD Ryzen 7 1700 processor.
Got a response from AMD about PDEP and SAM:
— 𝐷𝑟. 𝐼𝑎𝑛 𝐶𝑢𝑡𝑟𝑒𝑠𝑠 (@IanCutress) December 11, 2020
‘Smart Access Memory does not depend on the performance of the PDEP instruction.’
The speculation about accelerated PDEP on Zen3 being a factor seems to not be the case.
All you need is the 2409 BIOS update, but unfortunately, benchmarks with the AMD Radeon RX 580 are showing that SAM isn’t making much of a difference in titles such as Shadow of the Tomb Raider and DOOM Eternal. Here are the results for the latter, courtesy of Wccftech:
AMD SAM Disabled:
- Run 1: Average FPS: 125.6 FPS | Min. FPS: 82.2 FPS | Max. FPS: 250.3 FPS | 1% Low: 83.6 FPS | 0.1% Low: 41.1 FPS
- Run 2: Average FPS: 123.0 FPS | Min. FPS: 87.4 FPS | Max. FPS: 251.1 FPS | 1% Low: 86.1 FPS | 0.1% Low: 75.7 FPS
- Run 3: Average FPS: 123.0 FPS | Min. FPS: 87.7 FPS | Max. FPS: 251.4 FPS | 1% Low: 83.6FPS | 0.1% Low: 73.5 FPS
AMD SAM Enabled:
- Run 1: Average FPS: 125.9 FPS | Min. FPS: 85.4 FPS | Max. FPS: 253.0 FPS | 1% Low: 86.0 FPS | 0.1% Low: 77.1 FPS
- Run 2: Average FPS: 124.2 FPS | Min. FPS: 82.0 FPS | Max. FPS: 252.9 FPS | 1% Low: 85.9 FPS | 0.1% Low: 43.0 FPS
- Run 3: Average FPS: 124.6 FPS | Min. FPS: 79.4 FPS | Max. FPS: 252.8 FPS | 1% Low: 81.7 FPS | 0.1% Low: 65.7 FPS
Overall Average with AMD SAM Enabled:
- Average FPS: 124.90 FPS | Min. FPS: 82.26 FPS | Max. FPS: 252.90 FPS | 1% Low: 84.53 FPS | 0.1% Low: 61.93 FPS
Final Results:
- Average FPS: +0.839%;
- Min. FPS: -6.20%;
- Max. FPS: +0.596%;
- 1% Low: +0.119%;
- 0.1% Low: -2.365%
“As you can see, most of the differences are within the margin of error while the minimum FPS take a huge hit which indicates performance degradation with AMD Smart Access Memory enabled on an older generation graphics card,” the author notes.
