i7 8700 coffee lake thermal compound application

fireflyserenity · 13 Dec 2017 at 08:23

Hi,

I can't find a recommended coffee lake specific thermal compound application method, I am using GC-Extreme thermal compound

on the arctic silver website it recommends a vertical line for i7 but they recommend this this method for up to 7th gen and coffee lake is 8th gen with more cores so...

in the past i've used grain of rice method on single core and centre line on quad core and not had any problems (I used AS5 on these occasions, don't know how GC-Extreme will differ) so I'm leaning toward vertical line but for the 8700 what do you think?

Thanks

mickyflinn · 13 Dec 2017 at 11:21

Thin application all over the cpu lid to ensure maximum coverage.

fireflyserenity · 13 Dec 2017 at 11:42

like spread it with a card or something?

mickyflinn · 13 Dec 2017 at 12:41

fireflyserenity said:
like spread it with a card or something?

Yes or whatever you have to hand but you dont want it on the retention bracket, also check how much your heatsink will cover the cpu.

doyll · 13 Dec 2017 at 15:22

i7 8700K die is rectangular so a cooked rice size dob in middle of IHS should spread and print almost to edges of IHS, and that is all the bigger print needs to be.

intel-core-i7-8700k-vs-7700k-delided-1000x506_575px.jpg

MrRockliffe · 13 Dec 2017 at 15:25

A pea sized blob will do - better to have too much than too little, as the force of the heatsink will spread it out evenly

doyll · 13 Dec 2017 at 16:19

Pea size might be okay. Depends on how thick the TIM is.
Keep in mind the IHS is too thin to tranfer much heat laterally .. only a few mm. IHS size is to distribute the cooler weight to edges of CPU PCB where it is supported by edges of CPU socket so the PCB does not flex and damage the 1000+ connections between CPU and motherboard.

We don't want a layer of time between IHS and cooler base. We only want TIM to fill microscopic voids between the surfaces over the area where CPU die is under IHS. Any spread of TIM and resulting print more than a few mm beyond area of CPU die is not helping heat transfer .. but may be causing TIM to remain in a layer rather than just filling voids.

The amount of TIM in a pea size dob is enough to do 2 or 3 rice size dobs. Experiment with a rice size dob and see how big it spreads. Image above show how big the CPU die is under IHS, so if rice size TIM is spreading into a big enough circle to cover it there is no reason to use a bigger dob.

A layer of TIM does not transfer heat near as well as metal to metal.

Air transfer heat at 0.024 W/m K;
TIM transfers at 6-12 W/m K
Metal transfers at 40-400 W/m K

fireflyserenity · 13 Dec 2017 at 17:06

Cool, thanks

it's the 8700 non-k cpu but it should be the same die inside?

doyll · 13 Dec 2017 at 17:12

fireflyserenity said:
Cool, thanks

it's the 8700 non-k cpu but it should be the same die inside?

I'm pretty sure both have same chip with K version not bing locked

fireflyserenity · 13 Dec 2017 at 17:20

Thanks mate

Doug2507 · 14 Dec 2017 at 08:07

Really doesnt matter. Just make sure it's a nice thin even application over the ihs. Never seen something so simple talked about so much as application of paste. You'll get a better temp drop by turning your heating down a degree or two.