Hey R,
4Ry is right, ya only need enough to evenly cover the cpu from edge to edge with a thin coat of Arctic Silver 10, (if your using that product) That's what I used for my processor.
Like 4 said, use isopropyl alcohol to clean BOTH surfaces, then apply a small bead of compound (about the size of a shotgun pellet) then carefully spread the compound outwards towards the edges. YOu will know if the spread is even by the way the coat lies on the cpu. Make sure you use a new razor blade, cuz any nicks on the razorblade will leave "tiny mountains" of grease when you spread.
Before I go any further, YOU DO have your mobo OUT of your case right? don't know about anyone else but I prefer the mobo out of the case when doing this because that way once the heatsink is seated on the cpu, you can get a good side view of the seat to be certain of a proper seat.
Once you have seated the heatsink on the cpu, carefully use a 1/4 twist turn side to side to assure a good contact. Then RE-ALLIGN the heatsink and clamp it down. DOUBLE CHECK for a proper even seat before you put it back in your case.
Now your ready to fire it up. I don't what anyone else does but I like to enter the bios in the hardware monitor section and I watched my cpu temp for a few minutes just in case I saw any temp spikes. That way I can always do a quick shutdown. If all goes well, then your good to go with your new beast !!!
Expect the cpu to run a bit higher than normal (say 5 -15 F ) for a while as the thermal paste has a chance to settle in. Arctic Silver says about 200 hours run time. And starting up and shut downs are OK because this will give it some heat settling after the case fans stop running. Now my Athlon X2 4800+ dualie runs as smooth as a "prom Queen's thighs" only not quite so risky
HOpe this helps bro, good luck to ya.
RIG specs
Antec P180 PerformanceSeries Mid-Tower Case
SeaSonic S12 600 watt power supply
Asus A8N32 SLI mobo AMD N-Force 4 SLIX16 (bios 1103 V02.58)
RealTek 97 onboard digital 5.1 Surround
AMD Athlon 64 X2 4800+ Toledo Core, 2 X 1mb L2 cache (AMD drivers w/MS hotfix)
2 gigs of Corsair TwinX3500LL Pro @ 437Mhz 2-3-2-6-1T
2- BFG Tech 7900 GT OC 256mg in SLI (nvidia driver 84.21)
Western Digital RAPTOR 74.3 gig 10-K rpm HDD for XP & Apps
Maxtor SATA II 250 G HDD for gaming, movies, MP3's
Maxtor SATA II 250 G HDD for document backup (unplugged)
Sony CD rom 52X
Plextor 708-A DVD/CD rom
Logitech Z-5500 digital 5.1 THX Surround 500watts