Hum........if you absolutely must have 1 of those 2 I'd go for the H100 as it's only £5 more expensive on Scan. I'm basing that purely on how surprised Tom was when he reviewed the H100 and I very much doubt the H80 could match the temps as the H100 would have as larger surface area on the rad (even though the H100's Rad is 11mm thinner it is 120mm longer) which = better cooling potential.