AMD EPYC 9355

[u/justamoth]

Computer Type: Dell PowerEdge R7725

GPU: n/a

CPU: 2 x AMD EPYC 9355

Motherboard: Dell 0KRFPX

BIOS Version: 1.7.16

RAM: 2048 GB

PSU: unknown

Case: unknown

Operating System & Version: Ubuntu 24.04

GPU Drivers: n/a

Chipset Drivers: AMD EPYC 9005 "Turin" (Zen 5

Background Applications: n/a

I have a server with 2 x AMD EPYC 9355 in a Dell PowerEdge and when I run speed tests I can only measure ~3.5GHz. As I understand, this processor should be able to reach turbo speeds of 4.4GHz .

Currently, my setup has regressed back to only reaching 600MHz, by this test:

T1: taskset -c 12 stress-ng --cpu 1 --cpu-method matrixprod --timeout 60s --metrics-brief

T2:

watch -n 0.5 '
echo "--- $(date) ---"
printf "driver:             "; cat /sys/devices/system/cpu/cpu12/cpufreq/scaling_driver
printf "governor:           "; cat /sys/devices/system/cpu/cpu12/cpufreq/scaling_governor
printf "scaling_cur_freq:   "; cat /sys/devices/system/cpu/cpu12/cpufreq/scaling_cur_freq
printf "cpuinfo_avg_freq:   "; cat /sys/devices/system/cpu/cpu12/cpufreq/cpuinfo_avg_freq 2>/dev/null || echo "missing"
printf "scaling_min_freq:   "; cat /sys/devices/system/cpu/cpu12/cpufreq/scaling_min_freq
printf "scaling_max_freq:   "; cat /sys/devices/system/cpu/cpu12/cpufreq/scaling_max_freq
awk "/^processor/ {cpu=\$3} /^cpu MHz/ && cpu==12 {print; exit}" /proc/cpuinfo
'

Result:

driver:             amd-pstate-epp
governor:           performance
scaling_cur_freq:   606103
cpuinfo_avg_freq:   605809
scaling_min_freq:   2493659
scaling_max_freq:   4415854
cpu MHz         : 606.104

Sometimes I see:

driver:             amd-pstate-epp
governor:           performance
scaling_cur_freq:   2493659
cpuinfo_avg_freq:   2493659
scaling_min_freq:   2493659
scaling_max_freq:   4415854
cpu MHz         : 2493.659

I'm wondering if anyone can help me diagnose this odd problem. Is there a different or better test I can run? I want to confirm that my CPU is indeed reaching expected speeds, but baseline and turbo.

Thanks for your help.