Acquired a delidded CPU, and I don't want to fry it

[Salsonn]

I recently bought a completed PC from someone who was selling it for a friend. The PC worked fine, ran through stress tests fine etc. So I bought it. At the time, neither of us knew that the i5-8600K under that cooler was delidded, and well after making the purchase when I had the CPU out of the socket and the IHS fell off because I wasn't holding it level. I was planning on moving some parts around, now that process is on pause for hopefully as little time as possible.

Admittedly I'm not interested in overclocking the CPU quite yet as it would be my first foray, I'm mostly just wanting to make sure I know how to safely handle/use a delidded CPU, as the only thing I'm confident on is not holding it upside down. I'm hoping this is at least a better if not the best location to ask. Maybe once I'm moderately sure I'm not cooking silicon I can start making use of the k in my SKU.

Under the IHS was what I can only assume is the liquid metal added by the original owner. I'm not sure how to tell if there's even enough on there, and since the IHS has fallen off, I don't know if I need to re-apply before attempting to power on the processor.

Okay, put into simple sentences, my questions are:

1. If the IHS falls off do I need to re-apply the liquid metal?
2. Is there a risk to leaving it as is, just placing the IHS back on and re-socketing?
3. Since I don't have any, if I need liquid metal, what should I get?

I need to get to sleep now, so questions will have a significant delay. Any advice is appreciated, and if I'm posting in the wrong place I'd love to know where the right one is.

 

[pastymuncher]

Personally I would clean the liquid metal off both the cpu and IHS and reapply fresh stuff. I would use TG Conductonaut but any liquid metal will do. Every cpu that I have delidded I have always stuck the IHS back on using some liquid gasket but this is my own preference as once I have done it it won't need to be done again. Don't put it on the edge of the IHS that makes contact with the PCB of the cpu, instead put a drop of gasket sealant in each corner of the inside edge of the IHS. All you need is just enough to make contact with the PCB and then clamp down the cpu holder in the motherboard before it sets for a solid fit.

 

[Ormy1]

1.) Probably. To be safe assume yes, you do need to clean and reapply the liquid metal.

2.) Risk is that the CPU will throttle constantly and you'll get very poor performance. Minimal (but not zero) risk you will damage anything, CPUs have many internal safeguards to prevent damage, although some of those may be disabled in BIOS. Worth checking. This is assuming the liquid metal hasn't got onto the CPU pins or anywhere else where it shouldn't be. If it has, you 100% need to clean it off first or it's much more likely you will fry something.

3.) There's less variation in the quality of different liquid metal compounds, they're mostly pretty good. Contrast that with thermal paste where some are miles better than others. As long as you get the liquid metal from a manufacturer with decent reputation (thermal grizzly/arctic/corsair/etc) it should be fine. Google for a review if you have any doubts.

Applying liquid metal takes much greater care than applying normal thermal paste, make sure you know what you're doing and get help if not.

 

[Nickolp1974]

As you don't seem very confident in this may I suggest that you just use regular thermal paste between the die and ihs, Temps will be a little higher that's all.

If you want to go down the liquid metal route maybe get some clear nail varnish and paint and tiny transistors etc on the PCB to ensure no shorts. And you want to put a small amount of liquid metal on both surfaces you are combining, use a cotton bud/Q tip to spread, takes time, be patient.

 

[MartinPrince]

As you don't seem very confident in this may I suggest that you just use regular thermal paste between the die and ihs, Temps will be a little higher that's all.

If you want to go down the liquid metal route maybe get some clear nail varnish and paint and tiny transistors etc on the PCB to ensure no shorts. And you want to put a small amount of liquid metal on both surfaces you are combining, use a cotton bud/Q tip to spread, takes time, be patient.

These would be my sentiments as well.

If you are not planning to overclock then I would think you'd be fine with quality thermal paste like Noctua H2, MX4 etc. The 8600k with its 6 cores doesn't run that hot, even mine that was at 5Ghz ran relatively cool, whereas the 8 core coffee lake CPUs gave out a fair amount more heat.

I would only really recommend using liquid metal if you might be heat limited for your overclock on the CPU which would mean that your temperatures would be in the mid to high 80s plus.

(PS don't use prime95 for heat testing use Realbench instead)

 

[bimbleuk]

I had an i5-3570k delidded for for 3 or 4 years. I had applied LM between the die and IHS. Before I sold the CPU on I lifted the IHS and checked the LM was still liquid and then spread it again with a cotton bud.

The advert stated the IHS had been removed and LM was the only thing holding the IHS on. The buyer installed the chip and had no issues running it. The the clamp on the Intel socket holds the IHS in place unlike a typical AMD socket.

So LM between the die & IHS preferably. Normal paste between the IHS and CPU cooler is plenty.

 

[Ormy1]

Liquid metal vs normal thermal paste will be a much bigger difference when used between the die and the IHS vs between the IHS and cooler because surface area. If you want good temps you can get away with decent paste for the cooler-IHS interface, not so much for the IHS-die interface because the die has a quite a small surface area compared to the top of the IHS.