They are both pretty damn cool and quiet compared to more or less any of the previous generations of top end cards from both ati and nvidia, if your not planning to overvolt and overclock the nuts off of them there wouldnt be much point imo unless your going to also WC your cpu.
Yeah as was stated for general use, gaming ect. you really dont need to water block the 500 series cards, run cool and quite even when pumped up a bit.
Depends on your needs, if you want to overclock it or you think the stock cooler isn't keeping the GPU cool enough or maybe you have a WC rig already and want it to include your GPU. I doubt it's worth it, they they keep pretty cool by themselves and should be fine for minor overclocking. You don't need to, but you cant if you want to sort of thing.
I cant say for how long the 500 cards last but if the past 4X0, 2X0, 5XX0, 4XX0 & 3XX0 generations from both brands are anything to go by then they wont last long.
I'd say if your in for the long run and want one or two of the current cards to last you past the next couple of gens I'd definitely water cool them. If your just after one card to last until the 600 series comes out, its probably not worth the expense.
Generally as a rule, you should water cool everything you possibly can, then think about how to make it work with the stuff you cant
My GTX 570 SC runs at 85C max on stock, its very high and i am considering to WC it. i think the past at the factory wasnt installed properly becasue it only runs at like 0.95V
My GTX 570 SC runs at 85C max on stock, its very high and i am considering to WC it. i think the past at the factory wasnt installed properly becasue it only runs at like 0.95V
They are not exactly cool, but they are quiet. If you want to overclock then Id say its well worth watercooling. If you dont then tbh its not worth it imho
I would say its worth it, myself i dont overclock my GPU only CPU but its still nice knowing i have the headroom if need be. Currently have a 5970 watercooled and noticed a drop from around 78Degrees at load on air to 43degrees at load on a watercooling loop but obviousley this will vary depending on the components you may decide to use i.e. waterblock, Rad.