Necessary to repaste processor?

[gregrocker]

Took out to carport a 7 year old Vista machine to blow out dust and install a case fan. Trying to get the CPU fan off to blow out heat sink and both came off exposing processor which still had wet paste. Hadn't planned on repasting processor so cleaned heatsink and replaced, blew out dust, installed case fan and reinstalled. Temps dropped from 40's to low 30's.

Do I need to plan to repaste since it hasn't been done and came apart. I'm asking because I'm not sure if the answer is absolute or negotiable. :huh:

Thanks.

 

[TVeblen]

Not sure I understand completely, but in general you need to have some paste (or "thermal compound") between the processor and heatsink - always.

If you are saying that the old paste was still "fresh", meaning it was malleable (spreadable), then sure, just reinstall with the old paste.

If the old paste was dried out and not malleable then you would then need to scrape off the old residue and reapply new paste.

If the paste is old and is still malleable them it was very good paste to begin with!

 

[gregrocker]

Must be, since it is at least as old as the machine which is 7-8 years, and still looked damp like toothpaste.

After running a few hours it's now up to low 40's on both cores. For an Athlon x64 4000+ Brisbane I found Maximum CPU Temperatures suggested 78c.. Any suggestion for maximum to repaste? Maybe 55c?

I had heard that once you peel the heat sink off it must always be re-pasted and wanted to double check that with someone I trust. Thanks.

 

[DavidE]

I've always read that you should clean and apply new paste any time a heat sink is installed.

A few times I have not applied new paste when re-installing a heat sink, and it has never caused any problems for me.

I'd say just keep an eye on temps for a few days and make sure they look ok.

I don't see why the max temp would be different if it's new paste or not.

 

[TVeblen]

I would think that when you are approaching say, 75% to 80% of the maximum recommended temp then it would require attention. But it depends on what you are doing. If it is hitting high temps under stress then it is grain of salt time. If it hits high temps at idle then that would be cause for concern.

The function of thermal compound is to fill the microscopic hills and valleys that actually make up the seemingly smooth surface of metal components. This fills the air spaces that actually insulates the heat transfer between components. The application only needs to be a very thin layer. A common mistake is to apply too much compound. You want some metal to metal contact with the compound filling the voids between.

Some people get real religious about applying thermal compound. But if you understand the mechanical concept then you can reasonably avoid unnecessary fuss and labor!

 

[gregrocker]

I think the temps are 10c lower due to blowing out significant dust and adding a case fan. I'm not worried about the temps now but will watch them on this machine going forward as I do all of our old machines. It's easy to have CoreTemp start up in SysTray.

 

[linnemeyerhere]

Greg, I just pulled apart a freshly bounded Zalman cooler set up for only a few weeks and afterwards I just added a small dab of fresh paste and installed my Corsairs H50 plate. I understand the material in your 6-7 year old system might seem viscous but I would always recommend cleaning and applying fresh to any system that has been running for more then 6 months. But just as tests have found that mayonnaise and other greases can work just as well as exotic compounds this material is really only filling the smallest of gaps and as long as the two surfaces are in close proximity you will get a good if not perfect thermal exchange.

 

[gregrocker]

Thanks, guys.

What temps do you like to see for your processors at idle and under load?

Is 36-46 with light internet browsing considered cool?

 

[mickey megabyte]

well that's quite a wide range, greg.

the important data is temperature under load.

a bit more paste can't hurt (after removing residue) - if you've got the time, inclination, and the paste.

 

[gregrocker]

Is Arctic Silver still out of favor? Last time I got the other stuff at Radio Shack. Cleaned first with q-tip and alcohol. Just a bead and let it spread itself. I still have the video I followed and saved for paste posters. I should ask you hardware experts for reviews.

 

[mickey megabyte]

bah, others may disagree, but arctic silver does the job.

 

[Ivan the SoSo]

As long as it's not total garbage (and the system runs that cool), I wouldn't worry about it.....Most of the difference between the pastes (that matters anyway) comes into play when you are doing the big overclocks....

 

[profdlp]

I always clean/replace mine, but that's partly because I wouldn't want to chance having to take everything back apart and redo it if the temps were high afterwards. Kind of an attitude that "a little bit screwed now" beats "doubly screwed later on". (This attitude does not necessarily apply to every aspect of my life, in case you were wondering.)

I think the only time I'd say "absolutely must replace" is if you encounter some of that old "bubble gum" stuff that was in favor with some of the cheaper companies a while back. That stuff wasn't worth a hoot to begin with. I also replace it's successor, the thin grey stickum pad that Intel (and others) like to use on their OEM heatsinks whenever I see that.

 

[SIW2]

I cleaned this machine a while ago.

Did exactly what you are suggesting - cleaned thoroughly with qtip and alcohol - then applied a tiny bit of paste.

Can't recall the brand of paste.

Is Arctic Silver still out of favor? Last time I got the other stuff at Radio Shack. Cleaned first with q-tip and alcohol. Just a bead and let it spread itself. I still have the video I followed and saved for paste posters. I should ask you hardware experts for reviews.

 

[pscowboy]

This is quite my forte since I built and maintained all of Price-Waterhouse's machines for three years.

Arctic Silver is still a great product. After the alcohol cleanup (cpu & sink), must polish the metal with a clean lint-free cloth to get off haze.
Credit card is best way for a consistent leveling. I put a dime-sized blob on cpu and run the card four directions twice, leaving a thin film; AND do the bottom of the heat sink with the remainder (same technique). Too much paste will compromise heat transfer. Place heat sink and wiggle, with pressure, about 1/4 inch in all directions. Clip and you're done.

On 24/7 server units, I re-pasted yearly (I could take servers down because of redundancy). Office pc's, after two-three years.

 

[ignatzatsonic]

Greg:

Here is the recommended application procedure for Arctic Silver 5, direct from Arctic Silver, for AMD processors:

Arctic Silver, Inc. - AMD® Application Methods

For most AMD processors, they recommend a single dot of paste, 5 cubic MM in size--2/3 the size of a BB.

That's a very small amount. If you look at various youtube "instructions", you will see people using way way too much paste.

 

[linnemeyerhere]

Greg,
Like wise I've always been the pea size dab in center guy and the proof has always been upon removal and in every case the paste has spread out nicely if not fully to the edges. I don't like to waste so I've never done the credit card spreader but I can see that it could be a superior method for getting all over coverage and not having to have the paste spread via pressure and heat as with the dab method. Either gets it done but care must be taken in the card method as you are getting the material all the way to the cpu edge and if over applied to both surfaces it could creep down to the pins .....heaven forbid.

 

[gregrocker]

Thanks, guys. It seems the video does show too much paste being applied. I'm going to stop linking it. A BB is smaller than a pea as I recall.

If your processor temps are in the 30's do you consider that cool?

 

[ignatzatsonic]

30's at idle is cool.

But CPU temps have a high correlation with ambient temps--if you boost your room temp by 10 degrees, CPU temps will jump.

As others have said, load temps are what matters. I wouldn't flinch until they got to the mid 60s.

I idle in the high 30s, but I purposely built a PC with low noise in mind rather than the lowest possible temps.

 

[linnemeyerhere]

Greg,
30's is perfect for idle and if that's under load then I'm having you install all my coolers from here out !