Do I Need More CPU Thermal Paste?

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Discussion Overview

The discussion centers around the necessity of reapplying thermal paste after unseating a CPU heat sink during a power supply installation. Participants explore the implications of not using thermal paste and the best practices for applying it, as well as methods for removing old thermal paste.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant questions whether thermal paste needs to be reapplied after the heat sink was removed, indicating uncertainty about the necessity of thermal paste in this scenario.
  • Another participant suggests that thermal paste is essential to fill air gaps and implies that the removal of the heat sink likely disturbed the existing paste.
  • A different viewpoint emphasizes the risk of damaging the CPU without thermal compound, while also noting that a lapped heat spreader might not require paste.
  • Several participants recommend applying a thin layer of thermal paste, with one suggesting a specific amount and method for application.
  • There is a reminder that thermal paste does not last indefinitely and should be reapplied periodically, regardless of whether the CPU has been unseated.
  • Multiple participants inquire about effective methods for removing old thermal paste, with suggestions including ArctiClean and rubbing alcohol, while discussing the pros and cons of different types of alcohol.
  • One participant shares a personal experience using a leaf blower to remove dust, while others caution against potential risks associated with this method.

Areas of Agreement / Disagreement

Participants generally agree on the importance of thermal paste for CPU cooling, but there is no consensus on the necessity of reapplying it after unseating the heat sink. Additionally, there are varying opinions on the best methods for removing old thermal paste.

Contextual Notes

Participants express uncertainty regarding the longevity of thermal paste and the specific conditions under which it should be reapplied. There are also discussions about the effectiveness and safety of various cleaning methods for thermal paste removal.

minger
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I just installed a new power supply for my desktop last night. In the process I needed to remove the CPU heat sink. With no thermal paste on hand, I just reassembled the heat sink. The question is simply do I need to clean the CPU and reapply thermal paste since the heat sink was unseated?
 
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You probably should, the thermal paste is designed to fill in the air gaps between the sink and the chip and taking it apart probably unsettled it quite a fair bit.
 
Unless you want to fry your CPU, you need to have some kind of thermal compound between the die and the heat sink. Unless of course you have a lapped heat spreader, then you don't need to worry about it.

If you apply thermal paste, make sure its a very thin layer. Did you remove the thermal pad that was there originally?
 
Definitely clean it and apply more paste. I only use an amount about the size of a grain of rice, then spread it evenly with a credit card or something like it. Unless both your processor and heatsink are considerably off from completely flat, it only takes just a little bit of grease. Less than you think.
 
Keep in mind that the thermal paste doesn't last forever, even if you never unseat the CPU...it will need to be re-applied in a couple years or so
 
What is commonly used to remove the old stuff?

(right now the box is sitting right under by my A/C unit so I'm not too worried for the time being)
 
minger said:
What is commonly used to remove the old stuff?

(right now the box is sitting right under by my A/C unit so I'm not too worried for the time being)

ArctiClean
http://www.arcticsilver.com/instructions.htm
 
minger said:
What is commonly used to remove the old stuff?

(right now the box is sitting right under by my A/C unit so I'm not too worried for the time being)

I always use regular old rubbing alcohol. It's cheap, removes every last speck, and leaves no residue.
 
B. Elliott said:
I always use regular old rubbing alcohol. It's cheap, removes every last speck, and leaves no residue.
Some rubbing alcohols have oils. You can get 91% or higher isopropyl alcohol from most pharmacies.
 
Last edited:
  • #10
Jeff Reid said:
Some rubbing alcohols have oils. You can get 91% or higher isopropyl alcohol from most pharmacies.

It depends on what you intend to do with it. 91% is perfect for what we're talking about here.
 
  • #11
Jeff Reid said:
Some rubbing alcohols have oils. You can get 91% or higher isopropyl alcohol from most pharmacies.
B. Elliott said:
It depends on what you intend to do with it. 91% is perfect for what we're talking about here.
Rubbing alcohol (70%) typically has some oil in it. 91% isopropyl alcohol typically only has water. I've seen higher percentages in the past at pharmacies, but not recently.

On a side note, I recently discovered that (electric) leaf blowers do a good job of removing dust from a computer.
 
  • #12
Jeff Reid said:
Rubbing alcohol (70%) typically has some oil in it. 91% isopropyl alcohol typically only has water. I've seen higher percentages in the past at pharmacies, but not recently.

On a side note, I recently discovered that (electric) leaf blowers do a good job of removing dust from a computer.

91% is the highest I've seen since I've been paying attention. If you want to spend a few extra dollars you could go ahead and get anhydrous isopropanol which is 99% pure...

http://www.parts-express.com/pe/showdetl.cfm?partnumber=341-407

I'm not sure if I would advise using a leafblower. With a leaf blower large amounts of air along with small bits of dust and debris are blown onto the motherboards surface which can cause static buildup. With small compressed air cans, there's no high velocity debris to worry about and you can more easily spot-clean needed areas.
 
  • #13
B. Elliott said:
I'm not sure if I would advise using a leafblower.
Although I've done this a few times myself, it was more of a note that it's possible rather than a recommendation. I did this with the case sides off. I didn't see any residual dust anywhere. Initally I tested on an opened power supply, then I tried it on opened desktop cases. You need to make sure there isn't anything that could be damaged from the high speed flow, like loosely connected wires or any debris of significant size. Also I would avoid over-revving any fans with the air stream.

Regarding isopropyl alcohol, I think 97% used to be availble decades ago at pharmacies, but I did a web search for it and don't find any hits. You can get 95% ethanol mixed with various toxic chemicals at some stores, and 99% isopropyl at some stores or online.
 

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