I'm a computer professional with over two decades experience, so I'm no newbie. But I have a question that sounds very newbie-ish: What's the best method for applying heat sink compound?

I've read all the online "how to's" and tried various methods, but my results never seem to be very good (temps in the mid 40's) and I fear damaging (another) processor (I once destroyed an old Athlon 1800+ by slathering on a layer of grease to the entire surface of the heatsink.)

Most "how to's" seem to agree on "thinly spreading a half-a-grain-of-rice sized drop of compound applied to the cpu die". But methods vary from "use a razor blade" to "dab with a gloved finger" (I'm using Artic Silver 5). And that amount varies well based on certain situations.

My heatsink is solid copper, but when I wipe it clean, I can feel it is not perfectly smooth, with microscopic ridges rubbing across my finger. So it's difficult to know exactly how much compound I need... the core is smooth (suggesting I need little), but the sink, while still relatively smooth, in fact isn't.

Too much compound can be as bad as too little. So any advice from other experienced builders would be appreciated. Thanks.

The proper quantity is more like split-pea size. Half a rice-grain is not enough. Think of it as smearing butter on a hard biscuit, you hardly see it, but you know it is there.
Use an old creditcard to evenly spread the paste on top of the CPU contact area only.
Wipe away anything that went 'over the side'.
When mounting the cooler, put it on, then twist and turn it gently just a little bit, to evenly make contact. Then tighten.
For best results, let it sit for 24 hours before powering on.

There are special compound removers, but Isopropanyl does the trick just fine.

I read an article a while back in PC Modder. It described a method (I am not sure of the term,Matching ? , Seating ? ahhhhhh I forget)
Anyway ,it amounted to sanding the heatsink block and the CPU top ,simultaneously with super fine Grits ,eg. 250 -400-800 . then applying the paste.Try a search at their Web . If you are really into it.
BTW there is nothing wrong with Cpu temps in the mid 40's

Good recomendations.

That's sounds better. I've always felt I was either under-doing it or over-doing it, so it helps to hear from someone else that has had good results.

What do you think about the idea I've read on some sites to wipe a tiny amount of compound onto the sink itself to fill in any gaps/pits/rough-spots? Is that even necessary after applying it to the die? Isn't that the whole point of heatsink compound anyway?

I haven't had much experience compared to Mugsy, but I've followed the instructions for using the Arctic Silver 5 (and did it a few times) and my 5 bux el-cheapo heatsink compound seems to work better than the stock silver stuff they use for stock P4 HSs.

Just in case you aren't sure which is the one, here's a link.
http://www.arcticsilver.com/arctic_silver_instructions_big2.htm

I've got the thermal paste covering the whole part of the CPU with just half a grain of rice of the compound.

If you had smeared the compound over your CPU, you'd create air bubbles, so I won't suggest that. If anyone had experience preparing a slide for a microscope, if you had an uneven water surface, you'd get bubbles in your slide. I'd think it'd work the same way here.

Also, I'd assume the guys who wrote that has already experimented a little on how to apply them, and has decided that this style made the best contact.

Also, I think it is a good idea to rub alittle of the compuond on the surfaces first. Just make sure you remove any access with lint free cloth, or a credit card