$20 will definitely get you better than stock...I believe my SLK-900A is like $29 so perhaps you should look into that, cause this thing works pretty damn good. Also yeah, it's $10 for a pretty small tube that's what I meant by expensive, but you can get quite a few uses out of a small tube so unless you're taking apart and putting in CPU's all day long you really don't need more than a 3.5 gram tube...that's how much I've got and I've used it like...8 times now and I knows theres still plenty left..it barely takes any to cover the CPU.....
yes you definitely need to get your CPU under 50 if you can and have 55C your full load and that being under something like prime95 and even then for my personal pref that is kind of high....my 2400+ XP with an aftermarket heatsink and a jerry rigged fan setup on the CPU is running at 55C Idle, but that's not my main machine and I believe that chip of mine tends to run hot, with stock heatsink it was up at 64C idle! So god knows what it was at during gaming...yeesh..
Also....concerning the paste...don't think that it'll just drop your temps like that *snap!*
the stuff takes 200 hours of 'burn in' time before it reaches it's complete stableness or 'homeostasis' I suppose you could say...so it takes a good week or two and then generally you can see a decline in temps usually like 2-3C at the most I've ever heard of someone getting is 5C which is pretty rare...you really aren't banking on the compound to get the good temps but more the heatsink..then the fan, then the compound, that's the list of importance in my opinion....
I don't know how much it'd help simply adding the compound to your CPU now, but I know it wouldn't be enough, best you'd see is 52C idle probably after it's burned in a little, besides that your stock heatsink will have a thermal pad on it and you don't want to put thermal compound on a CPU if the heatsink you're going to put on it has a thermal pad on it.
