I7 3970x very convex, high temps

[kosmarnik]

Hi!
Putting together a new system and noticed the cpu was very convex. So much that it didn't even make contact with the base plate of the HS (Mugen 4) on ~30% of the IHS.



I'll disassemble it and try to measure the profile of the IHS, but I never had such a convex cpu before.
Did some quick tests on stock and sure enough was hitting 85C on some cores after a minute or two with prime95.
There was also a +20C difference between the cores, sure some difference is to be expected but 20C seems excessive.
It was also running much hotter than 3930K I tested before it :|

What do you think? Should I return it or lap it?

 

[ATMINSIDE]

I'd be returning that.

 

[Bishoff]

Was that CPU purchased second hand? I've never seen anything like that before from a store bought chip. Seems like an excess of thermal compound being used as well, unless that's for the photo?

 

[kosmarnik]

I'd be returning that.

To early to tell.


I did add more pressure on the HS, but it didn't change much.

I went back and did some more testing, noticed the VID while running prime95:

Not only VID, but power draw seem excessive too.

Changed voltage to manual 1.3v in BIOS, and sure enough the temps fell dramatically along with the power draw (IIRC 155W).
Tried to reproduce this with voltage on auto, could not.

Must have been a BIOS fluke.

I have to test it out properly as the temps still seem high (~70C), although I'm using an air cooler, Mugen 4 push+pull.


The CPU is second hand.

 

[kosmarnik]

I need some advice people.
Been playing a bit in BIOS, vcore 1.35, LLC high, all cores @45x. Seems stable for now.
I ran wPrime and superPi for confirmation that the freq displayed is correct, and seems it is.


All considering it now seems pretty normal. Temps are average, but I'm using an air cooler so in the ballpark.

I do still have some BIOS weirdness, like not booting after a OC crash, but I gather it's the dual bios OC protection or something that fudging things. Will have to properly get to know the GB BIOS.

I only got 4x8gb 1600 RAM in there, but will put 32gb more from my main computer if this proves to be a stable platform.

I'll disassemble it tomorrow to check the CPU again (it's a PITA so I just benched today), but if it proves to be stable I just might have a go at lapping it.
Just want to be sure it's a keeper before I go that route.

EasyTune is the only thing that is showing at least somewhat believable vcore readings, don't know how trustworthy they are but they do correlate well with things I apply in BIOS (LLC, vcore).
ET reports 1.296v vcore under load @4.5GHz, seems ok-ish.

 

[ATMINSIDE]

That's a LOT of droop on the vCore... (1.411V down to 1.296V??)
Up the LLC and find where you're actually stable on voltage then.

 

[EarthDog]

What mobo is this on?

 

[kosmarnik]

That's a LOT of droop on the vCore... (1.411V down to 1.296V??)
Up the LLC and find where you're actually stable on voltage then.

LLC is on HIGH already,without it it was drooping to ~1.23v.
I'm still confused about the VID, even on stock the VID was insanely high (for stock) on load 1.4v?
After putting vCore manually on 1.30v the VID again showed up as 1.4v, but was (maybe?) correctly displayed in ET.
If I were to trust ET, my droop is 1.33->1.296v with LLC high, not that bad.
Any way 4.5 is stable at 1.33 BIOS/1.296v ET under load.

I'm still fresh with SB-E and x79 so still confused about a few thing.

I do get throttled back to 3.5 when I hit 80C (small fft), but I'm guessing that's tweakable in through BIOS.

So far 30mins of Prime95 blend settles the temps at 67-70C which seem ok.
It's only small ffts that up the power usage (225w) and temps to 80C.

Will continue to test tomorrow.
For now, what do you think? Worth keeping?

ARGH, as soon as I'm not looking something goes weird:
~20min of Prime95 blend and temps go up 15C all of a sudden:

It settled on a temp early on and stayed flat until is rose hit 80C was throttled to 3.5. what gives?

 

[kosmarnik]

What mobo is this on?

Gigabyte X79-UD5, F14b BIOS

 

[NiHaoMike]

Just to make sure it's not a fan control issue, retry the test with all fans (except PSU as that's usually not user adjustable) forced to max speed. If it's still too hot, try removing the side panel and using a desk fan to see if it's a case airflow issue.

 

[kosmarnik]

Just to make sure it's not a fan control issue, retry the test with all fans (except PSU as that's usually not user adjustable) forced to max speed. If it's still too hot, try removing the side panel and using a desk fan to see if it's a case airflow issue.

Nah, this is open bench testing, cpu fans on max ~1500rpm and 200m fan to get some airflow on the mobo.
I need to inspect it better, hopefully today.

 

[kosmarnik]

Nah, this is open bench testing, cpu fans on max ~1500rpm and 200m fan to get some airflow on the mobo.
I need to inspect it better, hopefully today.

Yeah, it's very bloody convex.
Explains a lot, 30% of the IHS is not even in contact with the HS base :|

 

[ATMINSIDE]

I'd be returning that.

^

 

[kosmarnik]

^

I'll see if that's an option.
If not seems it's a prime candidate for lapping.

 

[EarthDog]

IHS are typically not flat... are you tightening the cooler down enough?

 

[kosmarnik]

IHS are typically not flat... are you tightening the cooler down enough?

Yup, maybe even too much.
But definitely more than enough.

 

[ehume]

Nice shots of the convexity.

For keeping track of your temps, I'd recommend Real Temp. Not only will it indicate when you are throttling the cores, but you can also set it to log your temps. Very convenient on a timed run. You can read the results in OpenOffice or Excel.