CPU socket temp vs. core temp

[Ahammer18]

I have been looking all over for an answer to this question:

What temp should I pay attention to? CPU Core temp, or CPU socket temp?

My specs:
Windows 7 64bit
16gb DDR3
AMD FX-9370 (w/ Coolermaster closed loop water cooling system)
ASUS M5A99FX PRO R2.0
AMD Radeon R9 280x
1TB HDD
Corsair GS800 800w PSU

When playing GTA V I'll pull 72c on the socket, as measured by HWMonitor, but only 50-60c on the core temp. Are either of these temps alarming?

 

[ingtar33]

ok... i'll answer your question with a little explanation thrown in.

FIRST: you should know piledriver cpus don't actually have a temp thermometer on them. They use an algorithm to "guesstimate" their core temp. Your motherboard DOES have a thermometer on it. so lets start with that knowledge firmly placed in our heads.

On the FX lineup of piledriver cpus typically speaking the "core" temp reported is known to be rather inacurate... and usually far too "cold" to be a legit core temp. even when reporting it's temp's correctly, the piledriver cpu will report a "core" temp that is probably much closer to a "surface" temp then anything else. As a result, most people simply assuming the "actual" core temp is probably a little warmer then the "socket" temp the motherboard is reporting.

this is where it gets interesting though... see AMD knows the core temp reported by the cpu is "wrong" and as a result they built several max temps into the 990fx, 990x and 970fx chipset;

1) core temp of 75C - if your cpu ever reports a core temp of 75C which the motherboard judges to be a "real" temp your cpu will be temp throttled by your motherboard
2) motherboard SOCKET temp of 72C - if your motherboard ever reports a socket temp of 72C the motherboard will ASSUME your cpu is overheating and throttle the cpu back

SO - if your motherboard is reporting 72C on the socket it is definitely going to throttling the cpu back REGARDLESS of the temps reported by the cpu itself. I would also assume that your cpu isn't reporting it's temps accurately, as typically the standard piledriver behavior is for the reported CPU temp to be about 10C cooler then socket. So typically people don't see cpu throttling until the cpu core temp hits 62C + or so and the socket is hitting 72C...

NOW: there are some things you can do to cool your socket/cpu down, as those are hot chips that need more then just a closed loop water cooler to keep everything from temp throttling.

1) put a small fan over the VRM heatsinks (between the cpu and Io panel on the motherboard)
2) put a small fan BEHIND the motherboard blowing on the back of the socket

if you do both you'll see a significant drop in temps across the board, heck one might be enough.

 

[Ahammer18]

Alright, thanks for the quick and thorough reply, I'm sure you get these kind of questions often. Im probably going to have to move the radiator around, as it is right above what I assume is the VRM heatsink. Heres a pic: http://imgur.com/W4Jfs2o

Any suggestions? I have plenty of fans that I can spare, its just its going to be a pain in the ass mounting them.

 

[ingtar33]

you're right. the VRMs are covered by that radiator.

as for fans... i have used several different methods to cool vrms. one is to suspend a 120mm fan with fishing line over the vrms. Another is to buy a one or two 92mm fans and use some double-sided tape to secure them to case suspended over the vrms. both of these solutions work rather well.

 

[Ahammer18]

Alright, Im going to change the location of the radiator so I can mount a fan there, thanks for all your help!

 

[Ahammer18]

Alright, so I moved the radiator, put the rear exhaust fan back in place, and suspended a fan blowing directly onto the CPU/VRM area. Heres a pic: http://imgur.com/W4oMlmR

Hows it look? Temperatures seemed to rise much slower during the blend test in prime95. Also, how long do overclockers run prime95 to test their rigs?

 

[ingtar33]

Alright, so I moved the radiator, put the rear exhaust fan back in place, and suspended a fan blowing directly onto the CPU/VRM area. Heres a pic: http://imgur.com/W4oMlmR

Hows it look? Temperatures seemed to rise much slower during the blend test in prime95. Also, how long do overclockers run prime95 to test their rigs?

looks great. as i said, it might require a fan behind the socket as well, but you'll cross that bridge when you get there. as for prime. typically 12-24 hours. before i met this i5-4690k in one of my pcs i would have said i've never seen a cpu be unstable after passing an 8 hour prime burn. however that ended when this i5 passed a 12 hour burn and still was clearly and completely unstable.

 

[Ahammer18]

So this is what I've done on the back. Pardon the horrible cable management ;_; http://imgur.com/s2nWEve

 

[ingtar33]

that will do. you should see a nice drop on the socket/cpu temp after that.

 

[Ahammer18]

I have, its getting around 58-60c (not a horrifying 76c) for GTA V, probably even cooler for other, lighter games. Thanks for all your help!

 

[ingtar33]

no problem!