Same version, different frequency issue

[BoBo_W]

Hi ,I have a problem for version issue.

Why using the same test platform and DRAM, different versions of Memtest86 will display different frequencies.

11.5 ver. =>5600 MT/s
11.7 ver. =>2064 MT/s

[David (PassMark)]

We do fix bugs in this area fairly often, when new CPU models are released.

But in this case it might be the RAM speed is sometimes reduced to save electrical power.

[BoBo_W]

If it is an intentional power-saving feature rather than a bug, is there any way or setting to disable it so I can keep the RAM running at full speed?

[David (PassMark)]

It would need to be something set in BIOS.
On some machines there is a Package C State Limit (Intel) or Global C-State Control (AMD) setting. But we've never tested this to see if effect the RAM clock speeds.

Manually setting the clock speeds in BIOS might also override the automatic underclocking. Again, we haven't tried it and different machines might behave differently.

[BoBo_W]

However, the frequency variance appears to be tied to the Memtest86 version used, as the BIOS version remained exactly the same during the tests.

[David (PassMark)]

If you would like to post the debug log from both versions, we can take a deeper look
https://www.memtest86.com/tech_debug-logs.html

[BoBo_W]

Hi
Please see the attachment.
Thanks

[keith]

Thanks for the logs.

Since v11.6 for Ryzen chipsets, MemTest86 reported the actual memory speed used by the memory controller (~2000 MT/s), rather than the maximum configured memory speed (5600 MT/s) . As most newer chipsets have dynamic frequency scaling, this value may vary at different points in time based on memory load.

However, we understand this creates some confusion for the user so we are considering better ways to conveying this information so that the user understands that it is current memory speed which may vary over time.