AMD 13 7640 RAM Performance

My new Framework 13 with 7640 CPU is showing strangely low RAM performance. The 2 sticks are a 96GB DDR5-5600 kit from Crucial, Part number CT2K48G56C46S5. CAS Latency 46, 1.10V.

Memtest86+ V6.10 reports it all working as DDR5-5600 CAS 46-45-45-90 which corresponds to the Crucial specs. It also reports a low 22GB/sec bandwidth but Memtest86+ is more a correctness test than performance.

Linux runs fine with a 6.5 kernel.

When I test it I get bad latency and bandwidth.

Latency comes out to 200ns in a pointer chasing benchmark on a 256MB buffer.

Read bandwidth measures 15.5GB/sec.

Here are some numbers for other computers I can test:

Sandy Bridge Laptop – 87ns, 17.5GB/sec
Haswell Laptop – 73ns, 22.5GB/sec
Skylake Laptop – 66ns, 31.5GB/sec
Beelink AMD 5900HX – 90ns, 45GB/sec

Another poster described the same memory in a Framework 13 7840u getting 59.6GB/sec.

My BIOS is the new 3.03 version. It reports the memory as 5600.

Ideas? Has anyone seen anything like this? I have done the obvious things like reseat the sodimms.

Are the modules overheating? AMD 13 7840U Overheating Ram?

my memtest86plus screenshot is version 6.20 though dunno if that matters. why are you running even older version? good luck.

I don’t have anything which reports the RAM temperature. The usual sensors command has nothing to say about it. The BIOS doesn’t show temperatures the way most PC BIOS do.

It doesn’t act like high temperature. I get the same exact performance if I run the machine for a long time or turn it on from cold.

The RAM mounting is suspicious for power dissipation. It has a fiber cover which goes over the SODIMMs. I think they are there to prevent electrical contact. Can’t be good for heat.

The laptop is parsimonious on power. When plugged in I get at most a 22w draw unless the battery is charging. Running all 6 cores with an integer compute bound load it will throttle down to 2.7GHz but I will rarely hear the fan. I can get the CPU temperature, it rarely goes over 55C.


Memtest version 6.10 is what I had in my Linux setup kit. I just fetched V6.20 and let it run. No difference is apparent.

Mark_Christiansen: i just fired up my ventoy usb key, with memtestplus 6.20 x64 iso file on it. and selected memdisk or so mode/flag (in ventoy menu) and then memtestplus started displaying the same speed results etc from my original posting back then. even on battery only mode (no ac power adapter attached) current bios. all the same.

usb-A module in the more front / forward extension slot, on the right side of the frame work 13 amd laptop. all normal.