The 800 is taller, I think that's about the only difference. I have the SLK-800 and I'm really, really happy with it. I'm sure the SK-7 is nearly as good, and for that price, it's a great deal. If I buy a heatsink for one of my other rigs, it would be a SK-7. I'm actually thinking about getting one for IC11 so I can put on a 80mm fan.
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Main Rig: ASRock 939Dual-SATA2, Opteron 165 @ 9x275=2475, 7600 GT
Laptop: Dell 1520, C2D @ 2000, 8600M GT
Icrontic_11: Asus A7N8X-Deluxe, Barton @ 13x170=2210
