7950X3D PBO and Thermal Limiting

Background: This is my first AMD build since I had an Athlon XP so I’m stumbling around trying to understand the PBO scaling and thermal limits. I’m using the Asus Prime x670e-pro wifi with the latest bios and I’m cooling with an EKWB AIO.

Using Cinebench r23 I’m getting a score of 36626. With CPUID HWMonitor; The cores will max out around 5200 on CCD0 and 5700 on CCD1 which seems correct but they hang around 4800 and 4900 for most of the run. This is after turning on PBO (I don’t see anything for “PBO2” which I’ve seen on a few videos) and I’ve set the thermal limits to 90c in the bios. I can’t get the package temps above 80c which makes me think that it’s being thermal limited in a way that I don’t expect it to.

I know this isn’t a CPU with hardcore overclocking features but it feels like I’m missing something.

What would be the next steps? Voltage and Clock settings seem somewhat limited in the bios and I’ve not tried that path yet. Is there a tool to check what the CPU thinks it’s thermal limit is?

Are you overclocking? That CPU has an unlocked multiplier so if running at base freq’s you may not hit TJ-Max. Same with memory, do you have that maxed out?

Remove the power limits (not temp limits), but don’t touch the voltage on the CPU.

It’s likely that the power limits are what is limiting your CPU as there are a lot of cores there.

Official specs say max temp is 89C (vs 95 for the non-3D parts). As it’s a very recent part, are all drivers and bios up to date? Fresh windows install?

I’d expect the ccd1 to run a little faster (my 7950x runs around 5.2 at 90c on cinebench sith a noctua d15). For the ccd0 I’m not sure but 4.8 seems reasonable. How do single or low threaded apps run?

The x3D doesn’t clock as high and has hard power limits so you don’t cook your cache
I don’t recall if you have the same settings or not but if you set it to advanced, set power limit to motherboard
Set frequency override to +200
You can try a negative curve of -5 it might be stable it might not, you can try increase this to -10

@GigaBusterEXE When you say negative curve of -5 you mean the final value should be -5? I ask because the settings in the motherboard I have to pick the sign of the value then the value; which seems pretty odd honestly but I suppose they didn’t want to have to parse it.

@quilt yes I think I grabbed all the latest code that I could find out there but I’m still a bit new to amd and it seems that they have more drivers needed than I have needed to use on Intel build; that could also just be me not being on this bleeding edge in a long time.

You pick the sign then put 5

You’re silicon quality will determine how high you can set that, use few core/single core loads to test if it’s stable
If you’re chip is really bad, you might not even get -5 out of it, closer you can get to -30 the better, but likely won’t get that highif you want to disable, set to 0 then turn off sometimes there’s a bug where it keeps the previous value when you turn it off

Thank you for the help! I seem to be able to get to -16 in a stable way which is a bit disappointing but it’s still a great chip. I guess my misunderstanding was that the temp was the limit that get hits the most especially with so much stuff out there about delidding I’ve seen. So my findings seem that no matter how long I run it at 100% with 120w (more like 117) it’s not going to get over 80c so not much more to do with the cooling system.

I just got a 7950X3D system as well and am seeing the exact same behavior on an MSI X670E Carbon board, so not even the same manufacturer. With PBO enabled and despite not hitting any of the ‘traditional’ limits (temperature, PPT, TDC or EDC) the CPU will not draw more than ~120W, or about 150W total for the whole package, SoC included. It has to be an intended limit for these X3D CPUs.

I’ve configured CO as well, with -23 on CCD0 (the cache CCD) and -20 on CCD1, which in practice improves performance a bit while also lowering temps. The CPU just about hits around 80C, so there wasn’t a lot of room left to push more power into it anyway.