I own an AMD X2 4800+ cpu. About 6 months ago I applied thermal grease when I assembled the pc. How often do you have to apply thermal grease to your cpu and how do you get rid of the old thermal grease? Thanks.

You only need to do it if you separate the heatsink from the cpu. You can clean the old grease with a little alcohol.

You are supposed to used 99% pure Isopropyl Alcohol, not the 70% stuff which has stuff in to make your skin soft.

If the thermal grease is really old and hard to remove try a very small amount of WD40---works wonders! =)

Oh and I usually just use a tissue to clean the old stuff off but I shake it out first to try to get it "lint free" and I put the alcohol or the WD40 on the tissue and wipe.

As for the how often question. Only when you remove a heatsink from a CPU/GPU do you need to clean off the old thermal grease and re-apply. If you use thermal grease like Arctic Silver it can be really "Cement like" so try to avoid pulling up on the CPU/GPU package when removing the heatsink. The best method is to turn the heatsink slightly to break the bond before lifting it away.

Thanks for your help, but you still haven't answered my other question, how often do I have to change my thermal grease? I'm asking this question because my cpu temp went from 30 degrees C to 40 degrees C and it's in almost idle mode (light usage-internet). Thanks.

That is the thing - you shouldn't have to change your thermal grease unless you remove the heatsink. Dust is probably the culprit in this situation.

Try taking a can of Dust Remover(aka: Can of Air) to the processor heatsink, and blow all that gunk out.

We both answered the question. You only need to do it when you separate the CPU and the heatsink.

You should look at some other factors for your temperature rise. Have you installed any hardware lately.
The video cards run very hot. An extra hard drive will add some degrees to your system.
Be sure to clean all the dust. Make sure all the fans are working.
Check to see if your case has a good airflow, a closed space for your PC will make it hot.
And last but not least IT´S SUMMER! Here in sunny Mexico we get to 100 degrees or more almost daily that will make any PC hotter.

He did kinda answer your question. You shouldn't need to change thermal paste like you would oil in a vehicle. Maybe after 3+ years of hard use may the paste not be as pasty then you can change it.

The most likely reason that the average temp. have gone up is the ambient temperature in your room. It is hotter out now and people will overclock lesser (me) or whatnot.

Well my system temp right now is at 30 C. Here in NY it only reached 85 F today with 100% humidity, but I keep my ac on all day. Oh yeah one more question wouldn't alcohol damage the chip in a way. I read about some product that is used to remove thermal paste, but I forgot what it was called and how it worked. Thanks.

Alcohol will not damage the chip in any way - as long as it does not touch the actual chip(does that make sense?). Most cpu's(unless it is one of those notebook ones), do not have their core exposed. My advice, don't worry about it.

About that product that removes thermal grease, go here to get it:

http://www.xoxide.com/arctic-silve [...] l-kit.html

Works wonders.

Oh yeah! I was on xoxide today, and I completely forgot about this product. This is where I saw this product before. Thanks everyone for you help!

Cheap no-name TIM can dry out and get crusty in a short time, especially if theres a lot of dust in the case. It wouldn't hurt to check on it every year, or less, and reapply some fresh TIM. It won't cost you much for peace of mind.

What is TIM?

Thermal Interface Material. Thermal paste or the thermal pads that were put on by Intel.