Cooling CPU & Two Video cards, one loop?

[Ohmycaptain]

Hey guys, so soon enough I'll be watercooling my rig in my 800D. I plan on grabbing a 360 rad and doing a single loop over two 7000 series AMD cards, and an i5-2500k processor.

Just wondering if a single loop with CPU + 2x high end GPU's (right now I have two GTX 570's, will upgrade to two high end 7000 series when they come), will be fine with a 360 rad?

I'll be using a push/pull config with some Apevia UV Blue 120mm fans, nothing that great, I know, but I like the look of them over any other Blue LED fans I've found. I don't have the other 3 fans so I may just throw in some better fans at the top as a pull and use the apevia's as a push. I don't know how that will work though, I've heard different things about mixing fans and how it's bad in a push/pull config, some say it's not bad at all and doesn't matter, so any advice on that is welcome as well.

As for other parts, I plan on grabbing a dual bay res, 3/8 tubing, and an MCP655 water pump. Not sure what rad/blocks I'll be getting though, especially since the 7000 series hasn't even come out yet. I'll get the best 360 rad I can buy (whichever that is), price isn't a concern, so you can pretty much bet that I'll be grabbing the best possible parts for my cooling.

 

[AngryArtichoke]

The general rule of thumb is 120mm x 120mm of radiator space per major heat source, at minimum. If you want to overclock, I'd add an additional radiator.

You might want to consider getting the MCP355 pump instead. It has higher head pressure, and works better when you have a more obstructed water loop.

Here's my rig with some radiators added for some inspiration:

Larger pic here: http://i.imgur.com/ZyQX9.jpg

 

[Ohmycaptain]

The reason for single loop is cleanliness, I want the cleanest build I can possibly get. I don't want tons of tubing

 

[AngryArtichoke]

You can still run an additional radiator in a single loop.

 

[Dr.GumbyM.D.]

A single loop with CPU and 2x GPUs should be okay, but we don't really know anything about the 7xxx series (or NV's next contender), so I can't say anything for sure.

Right now I run my sig rig (2600k + 2x6950s overclocked) on a single Black Ice GTX 360 radiator with push only fans with no problem. My temps are never over 55c, almost regardless of room temperature. The only time it was over that when I was really hot-rodding my video cards with very high voltages and running furmark (totally unnecessary and unrealistic benchmark) just for the sake of seeing how high I could take my cards. Then the CPU temps got to 60c with furmark and 4xprime95, with GPU temps hitting 50c. The room was also at 28c for reference.

You'll likely be fine. I wouldn't hesitate to add another 6950 overclocked to my loop if I had the money for it, for a waterblock, and for a new PSU.... But since I don't, can't help ya there.

For push/pull fans, you want them to be the same rating (or very similar) so that one fan isn't just sitting there pushing against a slower/lower flow/lower pressure fan. It could hurt performance if one fan is drastically weaker than the other, since the weaker fan is just blocking flow. I wouldn't waste the money and space on getting two different fans for push pull. If you've got the room, I wouldn't hesitate doing 38mm deep fans like I've got now (Panaflos), but if I wanted quieter fans at all RPM, I'd go with GT AP15s. I'm in the group-buy order for GT-2150s at overclock, so I'm going to give those a shot when they come in.

Also, a very important factor in your decision will be the radiator you choose. I happened to find a very dense radiator that can handle a lot of heat. Lesser radiators will not be able to keep up with as much wattage. Check out This review/comparison for more info on radiator efficiency.

I have on qualms with recommending the XSPC RX360 or Black Ice GTX 360. They're both excellent, and you'll settle on whichever one fits your situation better.