thermal paste spread unevenly after delidding

[aren332]

i made a stupid mistake of delidding a cpu (4790K) then using thermal paste (arctic mx-4) thinking it will improve temps. Basically, after assembling the cpu and everything, i noticed higher temps than before, opened the cpu, and the thermal paste was spread unevenly. What could cause this?

[PDifolco]

4 minutes ago, aren332 said:

i made a stupid mistake of delidding a cpu (4790K) then using thermal paste (arctic mx-4) thinking it will improve temps. Basically, after assembling the cpu and everything, i noticed higher temps than before, opened the cpu, and the thermal paste was spread unevenly. What could cause this?

Bad contact  ?

Anyway you should use liquid metal on delidded CPUs

[Levent]

its super hard to do direct die thermal paste and use stock ihs as well. It would take me 10-12 attempts before I get it right. Results would vary 30c between good and bad mounts with my 3570K. Go liquid metal.

[OhioYJ]

19 minutes ago, aren332 said:

What could cause this?

You used thermal paste between the IHS and CPU die.

 

I tried this a few different ways (different pastes, and two different liquid metals) just to experiment as I don't always get the same results I see repeated around everywhere. I found this one to be true, with delidding, you need liquid metal, thermal paste at best might get you close to stock temperatures. 

 

Probably worth mentioning, I know my 7700k that I delidded I read things about people claiming it would need to be "serviced" every year or two after being delidded due to the liquid metal. This one is now over 6 years old, still no problems, hasn't been touched.  It dropped my temps almost 20 degrees under load.  That being said, I wouldn't do again, and haven't. Just not necessary.

[OhioYJ]

1 minute ago, Levent said:

its super hard to do direct die thermal paste and use stock ihs as well. It would take me 10-12 attempts before I get it right. Results would 30c between good and bad mounts with my 3570K. Go liquid metal.

Even with liquid metal, I found there was a fair amount of variation in the results, depending on the application. There is a bit of an art form to it. Your results just won't be nearly as bad with liquid metal, compared to thermal paste, even on a "bad application."

[Levent]

19 minutes ago, OhioYJ said:

Even with liquid metal, I found there was a fair amount of variation in the results, depending on the application. There is a bit of an art form to it. Your results just won't be nearly as bad with liquid metal, compared to thermal paste, even on a "bad application."

I also found making a tiny shim out of one maybe two layers of electrical tape on the PCB made a noticeable difference (I did have the glue removed). Thermal paste on core die pumps HARD. You can hardly get 3 months of use out of it. It was a constant maintenance operation for me lol

 

EDIT: DONT DO THAT, I FORGOT THAT I LAPPED THE IHS.

[aren332]

Just now, Levent said:

I also found making a tiny shim out of one maybe two layers of electrical tape on the PCB made a noticeable difference (I did have the glue removed). Thermal paste on core die pumps HARD. You can hardly get 3 months of use out of it. It was a constant maintenance operation for me lol

 

EDIT: DONT DO THAT, I FORGOT THAT I LAPPED THE IHS.

how about i use a high quality thermal pad? something like this https://www.amazon.com/Thermal-Grizzly-KryoSheet-25/dp/B0C61NWNZH

[WereCat]

15 minutes ago, aren332 said:

how about i use a high quality thermal pad? something like this https://www.amazon.com/Thermal-Grizzly-KryoSheet-25/dp/B0C61NWNZH

Yes that will work. But have in mind that KryoSheet is also electrically conductive and is NOT reusable and it's not really easy to apply it as it can easily move around. 

 

Alternatively you can use PTM 7950. 

 

 

Btw the 4770k I delided back in like 2015/2016 still uns to this day in it's overclocked state with the original application of LiquidMetal (now in friends PC). 

 

- I just removed the glue from both IHS and CPU. 

- Applied nail polish for the small SMD components around the CPU die. 

- Applied LM on the CPU die AND on the IHS. 

- Put the CPU without IHS carefully into the MB socket THEN placed the IHS on the CPU. 

- Then carefully clamped the CPU in the socket while pressing on the IHS with a finger so that it wont slide

- Mount cooler and done (used thermal paste on cooler) 

[aren332]

2 minutes ago, WereCat said:

Yes that will work. But have in mind that KryoSheet is also electrically conductive and is NOT reusable and it's not really easy to apply it as it can easily move around. 

 

Alternatively you can use PTM 7950. 

how about if i spread the thermal paste on both sides, on the ihs and the die, could that be fine

[WereCat]

5 minutes ago, aren332 said:

how about if i spread the thermal paste on both sides, on the ihs and the die, could that be fine

No, the whole point of deliding is to create as small difference in Z height between CPU die and IHS and thermal paste vuscosity is not good enough and as mentioned, will pump out over time due to thermal cycling.

I have experience with LM, graphene pad and PTM 7950.

I say go with PTM 7950, almost all the benefits of LM without the hassle and risks. 

 

Also read my edit on previous comment. 

[aren332]

6 minutes ago, WereCat said:

Yes that will work. But have in mind that KryoSheet is also electrically conductive and is NOT reusable and it's not really easy to apply it as it can easily move around. 

 

Alternatively you can use PTM 7950. 

 

 

Btw the 4770k I delided back in like 2015/2016 still uns to this day in it's overclocked state with the original application of LiquidMetal (now in friends PC). 

 

- I just removed the glue from both IHS and CPU. 

- Applied nail polish for the small SMD components around the CPU die. 

- Applied LM on the CPU die AND on the IHS. 

- Put the CPU without IHS carefully into the MB socket THEN placed the IHS on the CPU. 

- Then carefully clamped the CPU in the socket while pressing on the IHS with a finger so that it wont slide

- Mount cooler and done (used thermal paste on cooler) 

also is this fine? i applied it, squeezed it, and took of the lid

 

[WereCat]

Just now, aren332 said:

also is this fine? i applied it, squeezed it, and took of the lid

 

No. TERRIBLE contact, too much space between IHS and CPU. 

Remove the glue from CPU... Use plastic credit card or somethingike that to remove it. 

[aren332]

2 minutes ago, WereCat said:

No. TERRIBLE contact, too much space between IHS and CPU. 

Remove the glue from CPU... Use plastic credit card or somethingike that to remove it. 

i have a knife, is that fine?  also the super glue is around the ihs, also it feels like the cpu is only touching the die, and i have to squeeze it so it actually touches the pcb. Idk how you think that is bad contact. Explain pls maybe im thinking wrong

[OhioYJ]

8 minutes ago, aren332 said:

 Idk how you think that is bad contact. Explain pls maybe im thinking wrong

Did you clean the old glue off of the CPU when you delidded the first time? The original silicone will hold the IHS away from the die. It is perfectly fine to glue it back down, but you want to use a very small amount, and not glue it entirely. Here is one of my CPUs, notice it's been cleaned entirely, ready for liquid metal, no glue around the edges (contacts have nail polish over them).

 

 

If you just popped the IHS off, and then tried to replace the thermal compound, and put everything back, that's another problem on top of trying to use regular thermal compound.

 

What you do between CPU die and IHS, and what do between an IHS and heatsink are different things.

[aren332]

5 minutes ago, OhioYJ said:

Did you clean the old glue off of the CPU when you delidded the first time? The original silicone will hold the IHS away from the die. It is perfectly fine to glue it back down, but you want to use a very small amount, and not glue it entirely. Here is one of my CPUs, notice it's been cleaned entirely, ready for liquid metal, no glue around the edges (contacts have nail polish over them).

 

 

If you just popped the IHS off, and then tried to replace the thermal compound, and put everything back, that's another problem on top of trying to use regular thermal compound.

 

What you do between CPU die and IHS, and what do between an IHS and heatsink are different things.

during expirementing before, ive put a dot in the middle of the die, then put the ihs back on. Ive noticed on the die that there was little to no thermal paste in the middle and most of it was on the sides.

Could that be because it was squeezed too hard?

 

also how strong is the pcb, is it safe to use a knife to scrape off the silicone?

[WereCat]

14 minutes ago, aren332 said:

i have a knife, is that fine?  also the super glue is around the ihs, also it feels like the cpu is only touching the die, and i have to squeeze it so it actually touches the pcb. Idk how you think that is bad contact. Explain pls maybe im thinking wrong

It's a bad contact because there is a glue and also because there is a lot of paste spread thick on the die. You want as thin spread as possible otherwise you are just using the paste as insulator instead of thermal conductor.

No, knife is not fine... unless you are sure you wont do a single accidental bad move and either scrath the PCB or yourself.

[aren332]

1 hour ago, WereCat said:

It's a bad contact because there is a glue and also because there is a lot of paste spread thick on the die. You want as thin spread as possible otherwise you are just using the paste as insulator instead of thermal conductor.

No, knife is not fine... unless you are sure you wont do a single accidental bad move and either scrath the PCB or yourself.

i got it to run 62c in prime95 small ffts non avx, with a single tower cooler stock clocks. how long will it last like that? in a year for example, will it still run just like that

[aren332]

22 hours ago, WereCat said:

It's a bad contact because there is a glue and also because there is a lot of paste spread thick on the die. You want as thin spread as possible otherwise you are just using the paste as insulator instead of thermal conductor.

No, knife is not fine... unless you are sure you wont do a single accidental bad move and either scrath the PCB or yourself.

pls answer how long it will last at low temps i need to know. I removed the glue and silicon completely, applied then applied thermal paste and covered it

[WereCat]

1 hour ago, aren332 said:

pls answer how long it will last at low temps i need to know. I removed the glue and silicon completely, applied then applied thermal paste and covered it

At worst few weeks until the temp starts to creep up due to pumpout after thermal cycling at best 1y-2y before you have to repaste.

[Blue4130]

On 4/24/2024 at 4:30 AM, aren332 said:

pls answer how long it will last at low temps i need to know. I removed the glue and silicon completely, applied then applied thermal paste and covered it

Nobody can answer that. It is an impossible question. It could last 20 years, it could die in 5 minutes.