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CPU 70c on idle after new PSU.. how to easily clean CPU/HSF?

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July 18, 2011 1:25:00 AM

Hi,
I just replaced a 580w PSU in my PC with a 1000w Silverstone ST-G.. got it working and now the CPU is idling at 70c.. it was always high recently, but mind you before it had a monster-hot 580w PSU that couldn't completely handle my machine, sitting just above it.. St-G is meant to be a lot cooler... So I'm looking at the cable management, but ultimately I'm suspecting I'll need to remove the HSF, clean it, clean the CPU, paste it, and replace the fan, which I've never done before..

Wondering specifically, will I expect to have to remove the motherboard to do this? Looked for tutorials on youtube and such but can't find a trustworthy source on this.. most tutorials have the mobo out of the pc but don't mention if it's req or not.. I had a bit of a struggle getting everything in and I wouldn't relish the idea of basically having to dismantle the entire PC to do this - as video card, ram, all the power plugs and the CPU's big complicated DrMOS heatsink all sit in the way of the mobo coming out..

How can I do this is as a first-timer simply and safely? Not afraid of a challenge but to dismantle everything creates so many new variables of potential damage or mistake-making..

EDIT: Forgot to mention it's a intel QC 8300 yorkfield.. supposedly QCs can be hot.. but I don't want to burn it out, i never even OC =)
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July 18, 2011 1:40:02 AM

If you're just looking to clean the CPU and HSF, you don't need to remove anything else. I'm guessing you just have a stock HSF, so there should be prongs on the corners of the HSF that you can rotate and "unlock", giving you the ability to detach it from the mobo and lift the fan straight up, off the CPU. Make sure to unplug the power to the fan as well.

After doing so, clean the dust off the fan. Also, wipe the bottom of the HSF with a solution, removing the previous thermal paste. Then remove the CPU, making sure to lift it straight up when doing so.

Clean the top of the CPU with solution, then reseat it. Apply paste to the bottom of the HSF and reseat it on the top of the CPU. Tadaa! Hope everything goes smoothly.
July 18, 2011 2:48:01 AM

Okay awesome one more thing before I get started as I think I'm making the order for thermal paste now (can't really do this until it gets here, can I?) ... if I use Zalman paste the paint-on kind, which says to apply to both the cpu and the heatsink fan plate (where cpu meets fan), do I still need to obtain one of those thermal pads I've seen used on tutorials? Or is the paste enough?

And as cleaning utensils work, I've heard alcohol as ++% as possible, but as for where to get a safe non-lint applicator I'm a bit lost.. should I order something online or get something layman-level from the drug store to clean it with?

EDIT: Would it be a better use of time and effort to go ahead and swap out the stock fan for something like a MASSCOOL 8W553B1M3 90mm Ball CPU Cooler while I'm already in the PC? As for installation as an issue, my PC's non-window side also comes off, so I have some access to the bottom of the mobo w/o removing the board..
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July 18, 2011 3:33:26 AM

Working sort of backwards . . .

The paste is enough. The newer microfiber cleaning pads and clothes, an old dish towel . . . all work well. But don't get paranoid about lint - clean the surface and if you left a bit of lint, remove it.

Would it be worth changing heat sinks? Well, its not good that your cpu is idling at 70C. But even with a stock heat sink you should be doing better than that.

That would indicate you have other issues . . . the "radiator" may be clogged with dust bits, preventing air flow. And/or you may not be exhausting enough hot air from the case. You can get a general idea of where your specific problems lie by checking for dust, and running the PC with the case open, even on its side (hot air rises). If you see a dramatic change in temps, that may mean your case is not exhausting the hot air removed from the chip.

Finally, the advice you got about r&ring the heat sink is solid. But, you may not be able to remove the heat sink, or re-install it, or experience so much difficulty you are afraid to push it in or pull it out any harder . . . without removing the mobo from the case.

Once you've dealt with the Intel pins a few times, you often learn what specific problem you're having, and how to jiggle things just right to avoid removing the mobo. But there's no guarantee you and your case/mobo/heatsink combination will go smoothly . . . without removing the mobo. Prepare yourself for that, and go ahead and do the job. Its not hard.
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July 18, 2011 3:51:22 AM

Wow! 70C on idle! That's hot!. You should not use your computer if you cannot get that temp down immediately. That means you're hitting well into the 90's on load or hotter and those kinds of temps can kill a CPU.

If it's at 70C right now, I have to assume your CPU fan is not set properly. Check if it is firmly seated. If it is not, then reseat it. This a "bad" recommendation because you never should permanently mount a CPU without a good application of thermal paste, but you're about to kill your computer so you can't wait for paste to come in the mail. Even though you don't have thermal paste, you'd do better than 70C idle with none. However, I recommend you just leave the old paste on when reseating right now. This should get your temps down into the 50's.

Is your CPU overclocked? Consider underclocking it until you get some thermal paste.

Do you have a discrete (PCI-e) graphics card? Try to find a weaker/cooler graphics card to use in the meantime while you don't have thermal paste. Or go to a computer shop and buy their overpriced stuff.

Do you have fans in your case? 70C rarely happens with decent airflow. I was only getting 60C idle on an overclocked i7-930 with a poorly mounted cooler in high humidity 85F ambient weather.

Do not take 70C idle lightly though. That could mean you hit 106C while gaming.
!