Rebuilding loop, can a passive radiator hurt flow enough to not be worth it? and more

[AndrewZorn]

Rebuilding my loop in preparation for the 2700k I just bought.

I don't think I'm going to liquid cool my 560 Ti 448 Classified like I once thought... it takes a long time to uninstall/reinstall (MCW60+ramsinks), will hurt CPU temps, and doesn't reduce the fan noise overall (except during games/load). Higher clocks are tempting, but I feel like I'll instead just be upgrading cards so quickly that won't much matter... I'd still like some input on this just in case this takes me all night and I'm very wrong about all this.

So that leads into the real question: by removing the GPU from the loop, I've decided to take out my second, smaller radiator which is an old Black Ice Xtreme single 120mm. Less fan noise, and the triple I have should be enough for CPU-only. Then I started thinking... why not leave it in, but passive? Would the resistance be worse than the extra bit of radiation it provides? I have an MCP655 and Apogee XT.

If the answer is "leave it in", I next ask how terrible it would be to cover up one side with a large fan. There's already a 120x38 fan on it, and I might even just leave it for optional use if you guys don't think the lost exposure would be bad.

I suppose this creates another option. Leaving in the thick, dense BIX radiator, and putting a slow normal fan on it. This would be very low noise, but more restrictive than just the triple radiator, of course... more complication too.

Thanks, and hopefully I get some quick replies because I'm off to go clean the blocks and try to decide if I should reuse this [expensive to me] tubing...

[Polizei]

Radiators add a bit of restriction but not much. The densely finned GTX radiators actually move a good bit of heat with just a 1000rpm fan, so anything is better than nothing.

[AndrewZorn]

So fan or not (but I'm thinking about a slow fan, just for exhausting if nothing else) you would add it (or, leave it)? Just want to confirm that you are advocating 'passive' use.

Radiator is similar to this, but with fixed fittings: http://www.madshrimps.be/files/image...DUR0N-3292.jpg

[stren]

I found that with 1 D5 adding a second radiator (even a low restriction radiator) to a cpu only loop hurt my temps:



Compare the data points with 1x450s @ 12V with 1/2 radiators, this was with 3 AP15's on the radiator also. So my guess is with a restrictive rad like a gtx that it would hurt you more than it would help. If you had two pumps or a very strong pump I'd say it would change though.

[AndrewZorn]

I dislike the indecision that comes from this conflicting evidence, but appreciate the discussion. Thank you. Maybe I'll watch a movie while I decide.

EDIT and is the consensus still "loop order does not matter", and I can put my waterblock right after the pump, without losing sleep over possible lower temps (were it right after the radiator)?

[Martinm210]

Depends on your water delta and system restriction. The GTX is higher than average compared to most radiators in restriction, so it's a little more of a question than most radiators especially if you're already running lower water/air deltas.

[Utnorris]

I would say you could run a couple slow moving (800RPM) fans and you wouldn't notice them. I run 9 Triberks at 800-900Rom range and can barely hear them and my water to air delta is within 3 degrees at idle and 5 degrees under heavy load. That's 2 x GTX580s (GPU only) and a 2600k overclocked to 4.8Ghz, vcore at 1.42v. My rads are the PA120.3's, old school. As far as flow goes, I run around .6Gpm for noise reduction. I never have noticed a temp difference between high flow and low flow with the newer generation of blocks that are non-restrictive.

[Polizei]

My loop runs pump > cpu > gpu > rad > res > pump and my temps are fine... I've never loaded both 100% seeing as I have a 2x120mm radiator (SFF guy somewhat), but I'm confident they wouldn't be through the roof. CPU load alone with GPU idle, I have about a 5 degree swing with a 21C ambient.