i7 920 / r290x crossfire loop question

Hi all:

Had a question about my current i7 920 @ 4ghz + r290x in CFX loop. Here is the background:

i7 920 @ 4ghz with raystorm block
2xr290x with xspc full blocks
Rads: 360mm + 120mm + 120mm
ap-15 fans all in push
d800 case

I used to have a gtx 690 in this same loop and temps were generally pretty good even with just 360mm + 120mm on the rads. Anyway, temps really started to go up when I upgraded to the 290x in CFX (not unexpected, since those things generate an unbelievable amount of heat). At load, CPU started to hit 75C+, and the GPUs would be somewhere in the 60C range.

So I added another 120mm rad. Temps didn't really improve - in fact, if anything, they increased. At this point, I figured maybe my d5 vario pump wasn't up to the task (speed setting had always been wonky anyway). So I swapped the d5/xpsc bay res for an mcp-35x/alphacool Repack Dual res. Again, no improvement. A bit stumped here - has adding the third rad added too much restriction in the loop? 120mm not enough extra to decrease the temps - but if so, why would temps even increase a bit?

I've also noticed that the back of the top 290x gets EXTREMELY hot at load.

Any thoughts? Thanks much.

I had a very similar setup. A 4930k and 2 x 290x. I was running it on a 180x2 slim radiator which I think is very similar to your total radiator size. Full load mining scrypt on GPUs was right about 60c. If I started a CPU miner it would go up to 64 on GPUs, but I don't recall what CPU temps were, but I don't think it was that high. I think that it should be cooler than your GPU temp, but I am not sure. I am in the process of rebuilding the loop and computer. I have been running the pump since last night and will check for leaks tonight. I have added 2 2x120 radiators and another 290x, but only have one DDC pump in the loop. I also changed my fans to ap29's. I can give more exact performance numbers after I finish getting it set up. I have more pumps to add if necessary.

Have you tried increasing airflow? I think you may need a bit more radiator.

Thanks. Thing is, though, when I increased from 480mm total rad to 600mm total rad, temps actually increased. That is what I can't figure out? Too much restriction?

Something doesn't sound right, have you looked at your blocks? Maybe there is debris in them, possibly from the addition of the radiators?

Definitely, you have an issue somewhere.
Are your gpu's parallel or series?
Perhaps you have excess restriction like a blockage or the nozzle plate inside the block -is it in correctly?

I now have added 2 radiators and temps are better on my cpu even though I haven't got plugs on the new fans yet. So, I have 1 ddc pump, a 2x180 radiator with two fans, 2 2x120 radiators with no fans yet, long lengths of tubing, and multiple 90 fittings. Even with my mediocre cpu block and a single weaker pump, my cpu temp is lower than gpu temps when everything is at 100% load.
Probably you have a bad mount or something wrong with your cpu block.

I ran a single D5 on a 420mm 280mm both 60mm thick and a 240mm monsta (80m thick) with cpu and xfires 7970's so it wasnt your pump at all. Most likely imho is you have more heat than you can dissipate. adding 120mm rad after 120mm rad is imho kinda as you say wonky lol. Get ya some good larger single rads 480mm 360mm and see what that does.

Most radiators seem to have a very low restriction, so I think you have something else going on.

Could you try one gpu load and cpu load and see how temps are?

S_I_N said:

I ran a single D5 on a 420mm 280mm both 60mm thick and a 240mm monsta (80m thick) with cpu and xfires 7970's so it wasnt your pump at all. Most likely imho is you have more heat than you can dissipate. adding 120mm rad after 120mm rad is imho kinda as you say wonky lol. Get ya some good larger single rads 480mm 360mm and see what that does.

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I hear you - if I had the room, I'd vastly prefer to just go couple of large rads. I don't really want to do external rads though, so I'm kind of stuck with where I am right now. Unless I go 900d, which I've been thinking about.

600mm is just shy of 240mm per heat source, though, and I'm not sure why temps would go up slightly after adding another rad if the issue was not enough rad....

also try reseating your blocks to the cards and gpu's might be having an issue there. you might also have an air pocket somewhere imho the d5 is way better pump than the 35x


another thought could be the new 120mm rad is picking up warm air instead of cool air. what are your rad locations??

I'm not sure why temps would go up slightly after adding another rad if the issue was not enough rad....

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Something doesn't sound right, have you looked at your blocks? Maybe there is debris in them, possibly from the addition of the radiators?

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Yep, will have to check the blocks next. Could also be a bad mount, I guess.

awesomepatrol said:

Yep, will have to check the blocks next. Could also be a bad mount, I guess.

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Or crap inside them.

Ok, wish I came much sooner when this thread was first posted. Could have cleared up a lot of things. I used to use the 800D for my first water cooling experience years ago.

First things first, do you notice any deposits in the reservoir, pump or fluid? Did you clean out all your gear before installing the new GPUs? Yes, the Xfire 290x's will produce more heat than the 690 but are pretty close in watts.

One thing that I can confidently say is the design of the 800, lets be honest, isn't the best air flow case by all standards nowadays. I personally believe that case is good for a CPU and single GPU only loops. Anything more I would look else where.

What is your airflow configuration on your rads? Where are all the rads setup? Too many questions and variables for me to assume. I can give you an example and say, the 120.3 is up top, the 120.1 is in the rear and the other 120.1 as at the bottom intake fan. If the bottom is intake and the top and back are exhaust, well there is a problem. Not enough airflow and you blocked the only place where the case gets its airflow from. Bad by design on the 800D since 120mm is the only intake feed unless you switch the top radiator fans as intake and rear as exhaust. Nonetheless its an old design and their newer cases show much better improvements.

I since have switched to the 900D and can say what a difference. You will end up overrading, well because you can. lol If you do have the funds your best bet is to grab one up. You won't be disappointed.

GTXJackBauer said:

What is your airflow configuration on your rads? Where are all the rads setup? Too many questions and variables for me to assume. I can give you an example and say, the 120.3 is up top, the 120.1 is in the rear and the other 120.1 as at the bottom intake fan. If the bottom is intake and the top and back are exhaust, well there is a problem. Not enough airflow and you blocked the only place where the case gets its airflow from. Bad by design on the 800D since 120mm is the only intake feed unless you switch the top radiator fans as intake and rear as exhaust. Nonetheless its an old design and their newer cases show much better improvements.

I since have switched to the 900D and can say what a difference. You will end up overrading, well because you can. lol If you do have the funds your best bet is to grab one up. You won't be disappointed.

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You nailed the rad setup - that is exactly how I have it. Sounds like this may be the problem.

I did indeed flush the gear and I don't see any deposits anywhere.

So it certainly sounds like ****ty air flow due to the addition of the extra rad may be the culprit!

Is there a solution without hacking the case apart to do the 240mm rad at bottom (which I don't really want to bother doing and would probably just get a 900d instead)?

awesomepatrol said:

You nailed the rad setup - that is exactly how I have it. Sounds like this may be the problem.

I did indeed flush the gear and I don't see any deposits anywhere.

So it certainly sounds like ****ty air flow due to the addition of the extra rad may be the culprit!

Is there a solution without hacking the case apart to do the 240mm rad at bottom (which I don't really want to bother doing and would probably just get a 900d instead)?

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I would honestly leave it alone with the exception of switching the top rad as intake instead of exhaust. I would add a filter to it so it doesn't dust up the insides and use the back as exhaust. You should get better temps that way.

Without hacking up the case which I didn't want to or deal with it I just had my 120.3 up top and 120.1 in the rear. You can see this in my old 800D build log in my signature. All headaches or any worries for anything literally for many and many years to come went away as soon as I got the 900D. Great airflow with all intakes with filters. There's some negatives about every case but this just has so many positives. Pun intended as my airflow is configured in positive pressure. I will be adding one more big rad soon for just a CPU and GPU only loop. lol It's going to be overkill (120.8 of heat surface) and I'll be done with plugging all the spots with rads.

Can I also ask what fans are you using and at what RPMs? Are your fans in Push n Pull? What radiators are you using exactly and what FPI count are they? Maybe we could figure something out here to lower the temps a bit but I would surely just switch the fans around to intake up top but make sure if you want it to be filtered or not.

Did you take the cpu block out and seperate it and clean the fingers with a toothbrush?

i had similar temp increases and when i pulled my raystorm block apart it had gunk in the fingers and what not and i cleaned it all up with a toothbrush and some alcohol and then a bit of vinigar after.

and made sure i mounted it in the proper position so the core was making full contact with water cooled area. and wala my temps droped like 10*C.

also make sure your air is not being recycled like said above.

And last point perhaps the XSPC full cover block for the 290x is restrictive but i would have expected the D5 to remedy that issue.

may have to check that block for gunk that might have got in the loop also .

I cant really see a single 290/x bringing more heat into a loop then a 690 so i don't see the physical heat input being your problem so i would stop looking at that direction completely.

I and many others run 290x in a loop without any added heat really.

my temps may have went up 1*C total if that adding the card to my loop from no card in loop.

I haven't taken the blocks apart. Maybe I will do that when I have the time.

But note that I'm running two 290x, not just one. And the heat that the two of these put off is absolutely nuclear.

I almost forgot to add, what fluid and biocide is being used in the loop? There's too many variables so we just have to break it all down. The amount of heat surface would be a minimum imo if it were to be low FPI and low rpm setup.

S_I_N said:

imho the d5 is way better pump than the 35x

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I beg to differ. lol I wouldn't go as far as saying the D5 is way better. All it has is just a tad more flow but lacks the head pressure and size the MCP-35x has. In a complex loop or restrictive, 35x's are hands down the winner. Don't get me wrong the D5's are great as well and can keep up.

Wait till the MCP-50x comes out. Last I heard I believe it was said that it was coming out in april. Gabe (Swiftech CEO) calls it a "pressure monster". lol

People just tend to think d5s are more reliable.. I also feel the mcp-35x is over all better as flow is still more than needed while having best pressure.. But reliability horror stories plague its reputation.


Also too awsomepatrol while I do agree the 290s are a fair bit higher watt Then the 690 aka dual 680s heat output. The difference should be small in water temperature so long as rads are keeping up on their end.

If you find no blockages then I would temp probe the water and see how much swing its having if water temps are holding strong its a block or flow issue.

If water temps are climbing you have either a fan pressure issue or not enough rads or your rads are recycling warm air somehow all basic easy to solve things.

Remember some fans cannot push air though dense rads very well or effectively.

I'm using distilled w/ kill coil. Fans are gentle typhoons all in push at default rpm. 360 rad is xspc rx360. The others are xspc ex 120.

So maybe I change the fans on the 360 up top to pull? Wouldn't that push a lot of hot air across the case? Maybe that doesn't matter now that I think about it.