When buying a cpu, will it come with thermal paste or do I need to buy some?
Usually comes with a thermal pad attached to the heatsink fan (assuming you buy the retail version).
You would probably be fine with the thermal pad but i would recommend using thermal paste in addition considering that it usually only costs about 50 cents / 1 dollar and it will increase the contact surface area (increased S.A. = better cooling)
Of course if you're gonna overclock consider getting something a little better like Arctic Silver (about $7.00)
If you by a reatail CPU it should come with some kind of thermal paste or pad. Even if it doesn't, you don't need thermal paste. I do, however, highly reccommend it. It helps to cool a lot. After all like others have mentioned it is pretty cheap.
yes you do need some kind of paste or pad. Manufacture paste is good but not great. Some CPUs that are sold alone do not come with anything. Arctic silver is a good thermal grease. I use it all the time. Excellent thermal conductor. A little goes a long way.
You mean use them both? No, would not be good. You must remove the thermal pad first before applying aftermarket thermal paste such as Arctic Silver 5.
If your CPU is an OEM product, and it did not come with a HSF, then you need to buy one. However, most aftermarket HSF units also come with pre-applied thermal grease. This means that there is no necessity of getting Arctic Silver 5 unless you are actually looking for a temperature decrease, since basic paste comes with about every CPU product out there.
Furthermore, Arctic Silver 5 is as good as it gets when it comes to thermal paste, and it lowers CPU temperatures quite considerably in some cases. The silver content in Arctic Silver 5 effectively fills the microscopic air holes (which trap heat) in between two solid objects (the surface of the heatsink and the surface of the CPU), helping heat transfer. As said before it is highly recommended.
Thanks, i'll see if I need to cool the cpu when it arrives.