i7 4790k - Temps help

[LtSkitzo]

Hi,

So I've just moved from an AMD FX-6300 to an i7-4790k; a BIG jump to say the least. At stock the i7 smashes the overclocked (4.6) FX-6300 by over 100% in synthetic benchmarks.

However, performance isn't my issue....well not primarily

When using something like like prime95 (small ftt) the i7's temp does not raise slowly, it jumps.

So unlike my AMD chip, which ticked up each degrees as the test went on, the i7 goes immediately to 75+ when the test begins, and then ticks up from there.

When the test is done, or I cancel it, it immediately jumps back down to around 30c -ish, where it usually idles.

Is this normal?

My cooler (h80i) only shows temps of 45+ (when testing), it's as if the i7 has a virtual temp which states what the temp will be, even if it isn't.... which eventually throttles it.

Any insight into this would be greatly appreciated.

[kalniel]

Yes. The chip has lots of powersaving measures that are reducing draw (=temps) when not under load.

What are you using to measure the temps and where is is measuring? (ie internal to the chip, the heatsink surface etc. etc.)

If you are getting throttling then it's likely an internal temperature is hitting threshold (or power draw is) before the heatsink can transfer the heat away. Might suggest too much thermal grease between HSF and CPU lid, or just too much voltage.

[LtSkitzo]

Hi,

Thanks for the quick feedback. Thermal paste is certainly not a problem, I only used the smallest amount (Grain of rice amount). I'm a massive enthusiast for my research when it comes to computers, but this part has alluded me.

As for measuring, well I never trust just one program, so I'm using RealTemps, Corsair Link, and MSI afterburner. Where they gather their information from? - I'd imagine it's internal to the chip.

I've only throttled when pushing the chip. So I know the issue there. I was more curious about the way it's instantaneously jumps with it's temp. I've not seen that before. I just wanted to confirm that was a normal thing.

[kalniel]

OK Yes the instant jump in internal temp is normal.

[EndlessWaves]

The 4790k is also half the size so even if all else were equal it'd change temperature more quickly due to it's smaller thermal mass.

It's not clear which temperature you're getting. You say it hits 75°C and climbs, and then you say it hits 45°C when testing.

I'd expect it to go to seventy five and climb on the stock cooler, but it shouldn't be going that high on any significantly better third party cooler, certainly not s an H80i.

[gupsterg]

When using something like like prime95 (small ftt) the i7's temp does not raise slowly, it jumps.

Which version of Prime95 are you using?

Why I ask is the latest versions use AVX and thus send temps higher.

Must OC'rs use version Prime95 v26.6 (Version History) plus other stability tests (handy thread to view).

Even after running a suite of stability tests (Intel XTU / RealBench / x264 / P95) I found doing folding@home for 24hrs+ continuously showed I needed to up 1 notch each vcore & vccring (CPU Cache voltage). The thing with F@H is each unit can stress machine different levels, so I ran it a few times but I do fold anyhow.

One thing I found on my mobo was the Auto setting for vccring can be higher at stock settings then required, I lowered it quite a bit.

What mobo & ram are you using?
What temps are you getting on cores after long testing?

Your very unlikley to see the temps P95 gets CPU to in normal use, I don't even see the same temps when F@H for 24hrs+.

[mrgreen009]

75+ is normal for something like a 4790k! I too was used to AMD's 65c and Intel was a shock, but they thermal throttle at around 100c to prevent damage anyway. But the cooler the better.

[thetwistedblue]

Yeh it's pretty normal. You can spend a good whack and get a massive cooler on it, but it'll still ramp up pretty quick

[LtSkitzo]

So now I'm rocking a full loop, and even though it is running slightly cooler I'm not super happy. The plan now is to delid and cool it naked. Risky I know, but I've heard the thermal difference is incredible.

[nexusmaniac]

No need to worry about temps jumping in Prime95
But be careful with Prime95 and OC'ing, it can cause your CPU to pull wayyy too much voltage when Prime is running L Which can be fairly deadly to your shiny new CPU haha
Also, if you leave your prime95 to run for 15-20 mins the liquid temp in the loop will equalise and temps have the potential to reduce slightly

[Sean473]

So now I'm rocking a full loop, and even though it is running slightly cooler I'm not super happy. The plan now is to delid and cool it naked. Risky I know, but I've heard the thermal difference is incredible.

The difference of 5-10C is not worth the risk of deliding... Haswell is really dangerous to delid due to FVIR... Get some good thermal paste and honestly 65-75C is fine for the 4790K... Mine hits 90C regularly in the laptop and it's fine.. Undervolt it a bit and you'll see quite a temp drop too!

[LtSkitzo]

Mega late reply/update

Although I decided against running the cpu naked, I did delid and introduce Liquid pro to the equation, following that I also lapped the CPU IHS > all the way through to 3000 grit, it took 2ish hours.

The temperature impact was amazing. Previous I was hitting 85-90c @ 4.6 (1.28), Now just 65-68@ 4.8 (1.31v)

What this says to me? Even though the 4790k is meant to have a better thermal interface compound, it doesn't compare to the previous soldered method used in the 2600k.

Intel made a mistake changing the way they do things.

[Bonebreaker777]

Even more ridiculous is the claim that the move was made to save money. 5-10p on each chip? When the company makes billions?

[kalniel]

Even more ridiculous is the claim that the move was made to save money. 5-10p on each chip? When the company makes billions?

PC sales aren't increasing, so a publicly owned company like Intel is beholden to increase margins by making cheaper chips for example. 10p a chip, for 100 million chips, might not seem a huge saving, but it's one of many things they'll be doing which when combined do make a difference (or offset a cost somewhere else).

[khanmein]

avoid running prime95, occt, furmark etc. i personally don't run any benchmark cos is worthless.

CPU itself is really beefy. most importantly, u able to run game smoothly w/o any hiccups or shuttering issue.