thermal compound not working after a few weeks - laptop

if the thermal compound applied to the CPU initially brings the CPU down to a cool temp, but the temp creeps up after approx 6 - 8 weeks, does that mean the tube of thermal compound was fake or did I apply it wrongly?

Reply 1

username5204820

Original post by errrr99

It's not necessarily indicative of either, there are many factors which affect temperature. It could be bad paste, it could be a poor application, or it could be some other issue.

Can you provide pictures of the thermal compound you used and the application? That'll be a good starting point to diagnose what's going on.

Reply 2

errrr99

photo IMG_1014 is before, photo IMG_1016 shows the dollop of thermal compound before putting the fan assembly back on

It worked so well initially I'd hate to take the blame for using a poor dollop technique - although I'm ready to hear the bad news, that the dollop was placed wrongly after all

Original post by errrr99

It's a bit difficult to tell, but did you clean the old thermal compound off properly? It's a dark photo, but I'd expect the CPU die to look quite a bit shinnier in the before photo.

In terms of how much thermal compound you've put on, I'll be honest it does look excessive. Placement is generally not an issue, as the pressure of the cooler should spread it out. For laptops it can be beneficial to lightly spread the paste in order to ensure good coverage though. But you shouldn't need a dollop of that size for the tiny die. Granted too much thermal paste isn't the end of the world, but ideally want as little as possible while doing the job.

TBH you're probably going to have to pull it apart to see for sure. I should have specified, but it's impossible to know whether the application is good from purely before photos. Really we'd need to see it after you've taken the cooler back off, as that could highlight patches of poor contact for example.

Can you clarify what sort of temperature differences we're looking at here? Are there any changes in your use case? What caused you to change the thermal paste in the first place? Are you seeing high temperatures immediately when turning the laptop on, or does it creep up over time?

Reply 4

errrr99

before thermal paste: temps of the 2 cores: approaching 80s - 90s just doing routine word and chrome use (few months ago)
after thermal paste application: initially temps around 40s - 50s now up to 70s - 80s again just for routine word/chrome use. The temp measurements are taken when a few programs are already running, I don't have a quick way to take the temp on start-up. I think the temp goes up with increased use e.g. more tabs open in chrome while word and pdfs are also running.

Cleaning the die: is the die the copper bit attaching to the CPU on the fan assembly or the actual black CPU? The CPU was quite shiny like a mirror...did not want to touch it unnecessarily to be honest! I had scraped off the old paste with sharp plastic.

I will follow your recommendations later this evening or tomorrow to get the "after" photos, and I'll have to find some alcohol first for cleaning up the excessive paste! I still have the same tube of thermal compound from January I'll be using that for the second time

Reply 5

username5204820

Original post by errrr99

Temps in the 80s and 90s from mundane use is not normal, 40s and 50s at idle and light loads sounds more like it. If you download something like CPUID Hardware Monitor, stick it on the desktop and run it immediately when you log in that'll give you an idea of temps on startup. That said, low temps initially and then ramping up when you use the machine is normal behaviour, but I wouldn't expect to see temps this high. Based on this, and the pictures from before, I'm starting to think you've used too much thermal paste and it's actually acting as an insulator which is why you're seeing temps creep up and stay high under load.

Original post by errrr99

Cleaning the die: is the die the copper bit attaching to the CPU on the fan assembly or the actual black CPU? The CPU was quite shiny like a mirror...did not want to touch it unnecessarily to be honest! I had scraped off the old paste with sharp plastic.

The die is the shiny bit of the CPU itself, the bit you put the compound on in the pictures. If it was like a mirror then that's fine, it's just the pictures making it look dark. You are right, you want to avoid touching it, however it is necessary to properly clean the old thermal paste off. Scraping the old paste with sharp plastic is absolutely not want you want to be doing though, and runs a risk of damaging the chip. Stick to rubbing alcohol or proper thermal paste cleaner and a microfibre cloth. A little dab of cleaner on the cloth and chip, then wipe with the cloth. Applying some pressure is fine if you need to, but avoid using anything sharp or scraping the CPU. The whole point of thermal paste is simply to fill in the tiny gaps on the die and copper plate, the last thing you want to do is scrape and make more gaps let alone damage the chip itself.

Original post by errrr99

I will follow your recommendations later this evening or tomorrow to get the "after" photos, and I'll have to find some alcohol first for cleaning up the excessive paste! I still have the same tube of thermal compound from January I'll be using that for the second time

Any idea what that tube is? If it's not a well known brand, may be worth picking up something different to use instead as it's still entirely possible it's just low quality paste. Also make sure you're cleaning the copper plate as well as the CPU itself. This video isn't great (and I really don't recommend using a screwdriver to poke bits of thermal paste off), but it should be a good visual aid for what I've described. Using cotton buds is an alternative to a microfibre cloth, just make sure you don't leave any fluff residue afterwards.

Reply 6

errrr99

In summary, I am going to aim for a tiny central blob next application...(the last dollop was bigger than a pea sized amount)

Arctic MX-4 (2019 edition) but I might be able to use another brand in about 2 months time or so (if I have the spare cash to buy or get it delivered etc)

Is the CPU die a bit soft? As it was shiny I thought it was metal but now I wonder if it's plastic like the old debit card I was scraping it with!

Is the tiny castor oil content of surgical spirit ok on the CPU as long as it is completely removed by the microfibre cloth? (less than 5% castor oil, 95% methylated spirit)

(edited 4 years ago)

Reply 7

username5204820

Original post by errrr99

In summary, I am going to aim for a tiny central blob next application...(the last dollop was bigger than a pea sized amount)

That definitely sounds like too much then and could be the cause of your issues. The recommendation for desktop CPUs is a pea sized amount, and laptops require quite a bit less since they don't have a heatspreader on top of the die.

As a general rule it's a good idea to apply thermal paste, put the cooling assembly back on, then remove it again and check the thermal paste distribution. You have to go a bit more careful with laptops since the assembly and screws are far more fragile, but it's much better to check your paste application before powering on.

Original post by errrr99

Arctic MX-4 (2019 edition) but I might be able to use another brand in about 2 months time or so (if I have the spare cash to buy or get it delivered etc)

Shouldn't be any need to buy new paste, Arctic are a well known and reliable brand. Unlikely to be any issues with dud paste.

Original post by errrr99

Is the CPU die a bit soft? As it was shiny I thought it was metal but now I wonder if it's plastic like the old debit card I was scraping it with!

It shouldn't be, the die itself is made of silicon and should be completely solid. If it's a bit soft you may not have cleaned off all the old thermal paste and that's what feels soft. It'd also act as an insulating layer, contributing to temps. Either way if you were pushing plastic into a CPU die hard enough for it not to feel solid you'd most likely have a dead CPU, so I'd guess it's leftover thermal paste.

Original post by errrr99

Is the tiny castor oil content of surgical spirit ok on the CPU as long as it is completely removed by the microfibre cloth? (less than 5% castor oil, 95% methylated spirit)

On that one I can't say for sure. A quick Google search sees some people saying it'll be alright if you're careful, others advising against it strongly. I would personally want to avoid any oil if at all possible so it's not something I'd really endorse. Not to say you can't and it's unlikely to cause damage, just that I'm not comfortable saying you can. Do some more research and use at your own risk on that.

For reference, this is the stuff I use.