So, I bought the Gainward reference GTX 970, happy as can be with it, but it runs a little hot (79-80 C playing Shadow of Mordor on Ultra).

So I'm curious about watercooling. I looked around and found that the NZXT Kraken G10 is a good fit, perhaps combined with the Corsair H55. Any suggestions, tips or help with this project? I've never mounted a water cooling device before.

I wouldn't water cool your GPU. The second you remove the stock cooler on your GPU you lose the warranty on your new hardware. It might not seem like it at first, and I would certainly not consider it ideal, but your card is perfectly find running at 80 C. My suggestion would be to spend the money on a nicer case so you can increase air flow, you would be amazed at how much of a difference just routing cables can do to your video card temps.

Now if you were using an older card for a hobbyist build, then fuck yeah, water cooling is a great way to reduce the PC noise. My experience with water cooling is from back in 2004, so I have no experience with modern closed-loop systems like the H55. My problems with liquid cooling come from the added care you have to take with your system, for example, there were times I noticed condensation building up on coolant lines. The condensation was so rare as to never be a problem, but I still had to get in the habit of cleaning my system after every use, just in case. For me, the extra chore of checking my PC at the end of the day made liquid cooling not worth the OC capability.

If you are cool with the extra care that needs to be taken with your system, then go for it. I love Corsair parts and I have heard that the H55 is a decent little setup, I am not sure about the Kraken G10 though. Their site mentions that their hardware has not been tested with the GTX 970's yet. I would look into something you know is going to work, or email NZXT and ask them for specifics.

I wouldn't bother spending money to water cool your GPU. Just put the cash away for a future upgrade or a second 970, those temps are within spec and it is designed to run at that temperature and higher before thermal throttling.

@monetarydread: I did check for that, and they said it should fit the card. But I have to agree with you, it's too much a risk to take just for some cooling. @mb Yeah, that's true. I'll rather check out airflow and perhaps add a second fan. Thanks for the input!

I wouldn't worry about that temp, I believe the throttle temp on the 900 series is 85. Almost all GPU's are built to run reasonably toasty. None the less if you are set on cooling the thing the Kraken does ok, however it lacks any form of direct contact cooling for the power delivery/regulation bits on the PCB. If those things cook then you are in big trouble, a lot of people tend to install a number of additional low profile heat sinks in order to cover this off. That being said Corsair are finally releasing their own bracket with the HG10 which will have a variant for each reference SKU, those have a full set of contact points to cool all the delivery components along with the mount point for an AIW.

@korwin: Thanks, and I've decided not to water cool it at the moment. I might down the line, after the warranty expires. That bracket from Corsair does sound interesting, it'll be interesting to see how it works out.

The past few generations of graphics card have actually been designed to overclock until they hit a clock limit or a thermal ceiling, whichever comes first. Your card is hitting the thermal ceiling of 80°C and maintaining it in order to get as much additional performance as possible without damaging the components. So there is really no need to worry about the temperature unless you start getting performance issues or visual artifacts when in-game.