AMD’s SAM now supported by 1st gen Ryzen processors

AMD's Ryzen CPU's are in a class of their own. And we know very the relationship between ASUS and AMD. As such, it is not a surprise that ASUS has…

By Nivedita Bangari

December 18, 2020

2 min read

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AMD’s Ryzen CPU’s are in a class of their own. And we know very the relationship between ASUS and AMD. As such, it is not a surprise that ASUS has decided to bestow upon its B450 motherboard the outstanding AMD Smart Access Memory support for first-gen Ryzen CPUs. The graphics and chipset manufacturers Smart Access Memory or resizable-BAR (Base Address Register) feature helps CPU access the full memory buffer available on any modern GPUs.

AMD is the first to offer this feature on its Ryzen 5000 and 500-series motherboards, but recently, the board manufacturers have unofficially extended the support on AMD’s 400-series and for Intel’s 400-series motherboards. There were already rumors of AMD’s SAM coming to the older generation of its CPUs, and now we are seeing ASUS enabling SAM support for even the 1^st generation Ryzen CPUs. AMD Smart Access Memory was enabled on an AMD Ryzen 7 1700 CPU running on ASUS B450-PLUS motherboard. The board was running the latest 2409 BIOS, which was released in early December.

Got a response from AMD about PDEP and SAM:

'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.
— 𝐷𝑟. 𝐼𝑎𝑛 𝐶𝑢𝑡𝑟𝑒𝑠𝑠 (@IanCutress) December 11, 2020

The user who successfully managed to enable SAM on his ASUS motherboard, tested the performance in Doom Eternal. Doom Eternal was tested at 1080p at Ultra preset. The results are as follows:

With AMD SAM DISABLED ON BIOS:

Run 1: Average FPS: 125.6FPS | Min. FPS: 82.2FPS | Max. FPS: 250.3FPS | 1% Low: 83.6FPS | 0.1% Low: 41.1FPS
Run 2: Average FPS: 123.0FPS | Min. FPS: 87.4FPS | Max. FPS: 251.1FPS | 1% Low: 86.1FPS | 0.1% Low: 75.7FPS
Run 3: Average FPS: 123.0FPS | Min. FPS: 87.7FPS | Max. FPS: 251.4FPS | 1% Low: 83.6FPS | 0.1% Low: 73.5FPS

With AMD SAM ENABLED ON BIOS:

Run 1: Average FPS: 125.9FPS | Min. FPS: 85.4FPS | Max. FPS: 253.0FPS | 1% Low: 86.0FPS | 0.1% Low: 77.1FPS
Run 2: Average FPS: 124.2FPS | Min. FPS: 82.0FPS | Max. FPS: 252.9FPS | 1% Low: 85.9FPS | 0.1% Low: 43.0FPS
Run 3: Average FPS: 124.6FPS | Min. FPS: 79.4FPS | Max. FPS: 252.8FPS | 1% Low: 81.7FPS | 0.1% Low: 65.7FPS

Overall Average with AMD SAM ENABLED:

Average FPS: 124.90FPS | Min. FPS: 82.26FPS | Max. FPS: 252.90FPS | 1% Low: 84.53FPS | 0.1% Low: 61.93FPS

Final Results:

Average FPS: +0.839%;
Min. FPS: -6.20%;
Max. FPS: +0.596%;
1% Low: +0.119%;
0.1% Low: -2.365%

It is not a surprise to enable AMD’s SAM support on an ASUS motherboard, but using an older generation Ryzen 7 1700 CPU is fantastic. Those who plan on running an older CPU/board combo with a modern GPU will benefit from this new revelation.

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