To those of you who have the H70. Is it worth it over the H50? I've bought high 110 CFM fans with a fan controller and I'll see how much it'll improve my temps. Note though that I am using Offset voltages so only under HEAVY load (Prime95 is the only program I've seen) do my temps hit the high 70s. Otherwise it's idle at 30C or load at 60C.
If you use speedstep then heat is not an issue during regular computing so I've been fine with just going with the increased voltage. My personal oc'ing policy is to go as high as you can while keeping the system stable. Then bring it down 5%. That'll account for any anomalies and keep your system a lot safer no matter what happens rather than riding it on the border.
As for h70 over h50...honestly I haven't used the h50. I know the h70 is better, but not better enough to justify the extra $40 price difference between the units here in Canada. But I figure if I'm using a lazy man's water cooling system, I may as well fork out a tad more to get as much cooling as I can out of it.
If you're planning on sticking to 4.5ghz-ish, I'm sure the h50 with stock fans would be enough.
I know someone who tried to OC the 2600k to 5ghz with the h50 and stock fans and it would only stay up for a minute or two before crashing and I'm stable at 5.2ghz with the h70 and 2 high flow fans.
And no they're not too loud. About 37dbm. They only spin at around 2200rpm. What may be a problem though, depending on the fans you have, is that while one fan is spinning at max speed, another fan is pushing a ton of air through it, causing it to spin at higher speeds than it can do on it's own, and this can result in a rather annoying hum or screeching noise.
Using quiet/lower cfm fans will help that. But the way I look at it...its still quieter than the fan on my video card so it muffles it out pretty much. Haha.