Cooling for i7-8700k @4.8 - 5.0GHz

[EarthDog]

What can we say about the multiple leaks showing much better results?

We have found, in the past, that setting all cores to the boost speed is generally successful. You aren't even there yet.

I don't do CPUs at OCF anymore, so I don't have one in hand.

 

[Vayra86]

Now that I can talk about these CPUs, I will say that no air cooler is sufficient for that sort of OC. One of my chips take 200W during AVX on all cores @ 4.3 GHz (which is basically stock).

Don't take advice from people who don't have this CPU yet.

It is possible that the BIOS on the board I have is a bit raw, and power use would come down, but I have a CoolerMaster Liquidmaker PRO 280 cooler on my 8700K, and it hits nearly 80c on all cores with these clocks.

AVX is not really the best guideline though, or am I misinformed. Its the absolute cap that you would never hit without AVX? What are your temps for non-AVX torture loads, same or ?

 

[EarthDog]

Seems his is about the only one that hasnt reached that high... including tpus other sample...

 

[ppn]

Well you dont have to measure power consumption from the wall "the der8auer prime95 8KB running AVX VRM melting style". It could be simply the highest possible doing normal things like Mediacoder x64 measured directly at the EPS12v the real cpu power will be 80-90% substracting the VRM inefficiency loss. 200 Watts is very impressive though i'd like to see that in detail.

 

[cadaveca]

AVX is not really the best guideline though, or am I misinformed. Its the absolute cap that you would never hit without AVX? What are your temps for non-AVX torture loads, same or ?

I can do 4.8 GHz @ 1.35V, 95c loaded.

 

[Krit]

I can do 4.8 GHz @ 1.35V, 95c loaded.

What cooler you are using ?

 

[Vayra86]

I can do 4.8 GHz @ 1.35V, 95c loaded.

That's pretty painful for 1.35v then oO Would not 24/7 that

@Verbatim: 'It is possible that the BIOS on the board I have is a bit raw, and power use would come down, but I have a CoolerMaster Liquidmaker PRO 280 cooler on my 8700K, and it hits nearly 80c on all cores with these clocks.' - cadaveca

The more I see these temps, Im edging towards the i5 8600k. Or perhaps go for water anyway. Or a delid.. lol!

 

[EarthDog]

I think, and dave can correct me here, but his is more on the below average side of things, no? Look at how many reviews are hitting 5 Ghz.. some on air. I am not sure how they tested those clocks, but clearly his, at that voltage is torturing his AIO. TPU's review shows 1.376V at 5 Ghz. Not sure how W1z tests for stability (is it listed there? I swear no game settings listed, no stability tests listed - I have to be blind.. where the heck is that necessary stuff?)

 

[Vayra86]

I think, and dave can correct me here, but his is more on the below average side of things, no? Look at how many reviews are hitting 5 Ghz.. some on air. I am not sure how they tested those clocks, but clearly his, at that voltage is torturing his AIO. TPU's review shows 1.376V at 5 Ghz. Not sure how W1z tests for stability (is it listed there? I swear no game settings listed, no stability tests listed - I have to be blind.. where the heck is that necessary stuff?)

Always expect the worst though I have seen my share of DOA and crappy hardware by now not to trust in luck of the draw - I do intend to buy cooling and CPU at the same time, so there's that little hurdle too.

 

[yotano211]

Now that I can talk about these CPUs, I will say that no air cooler is sufficient for that sort of OC. One of my chips take 200W during AVX on all cores @ 4.3 GHz (which is basically stock).

Don't take advice from people who don't have this CPU yet.

It is possible that the BIOS on the board I have is a bit raw, and power use would come down, but I have a CoolerMaster Liquidmaker PRO 280 cooler on my 8700K, and it hits nearly 80c on all cores with these clocks.

Can you see how far you can undervolt your processor at stock speeds.

 

[cucker tarlson]

Frankly this cooler will be heavy enough to bend the CPu substrate in the corners. I wouldn't put more than a single heatpipe cooler on that CPU and not to overtighten things.

I would.

 

[biffzinker]

For comparison, Corsair's 280-mm H115i produced a 90° C package temperature and core temperatures ranging from about 84° C to 90° C using the same settings and voltages with Prime95 Small FFTs. Blender topped out our overclocked i7-8700K at about 80° C at the package. The H115i definitely reins in the i7-8700K if you're shooting for the ability to run Prime95 for hours, as one might want to do for extreme stability testing.

Source: Just how hot is Coffee Lake? - The Tech Report