Pump ponderings
 

Recently added a couple of GPU blocks to my system, and they're pretty restrictive. Am thinking I may need a different pump. Currently run an eheim 1250, it's good, very quiet and does the job, but may not have enough head capacity.
I'm thinking maybe a MCP650 due to high pressure head, or some sort of alternative with similar or better high pressure drop performance.
So the questions:
How noisy is the MCP650? Assume it'll be mounted on a foam block to reduce induced vibration.
Will running it at ~14V (or more?) reduce lifetime significantly? I noticed 14V is the max listed on swiftech's site, wondering if the rated lifetime is for 12V operation only or anything in the 6-14V range. bill?
Any other pumps that would be a good buy (would prefer not to spend silly money)?

Just buy another 1250 and run it in series! That'll double your head to 13ft!

They're not small, also 2 1250s in series dumps near 50W in my loop! I'd rather use a single lower powered pump if possible.

In order to answer your question of "How noisy is a Laing D4?", it needs to be countered with the question of what your tolerance for noise is.

Some people (you know who you are! ;) ) think that if they can't hear something over the noise of their 40dBA PSU/CPU/northbridge/GPU/whatever fan(s), then that means that something MUST be quiet.

Some people think that the Laing D4's are quiet, while others find the whine of even the "muffled" pumps intolerably noisy. Just like how one person's definition of "super-ultra-spicy hot" food, is another person's definition of "very mild".

The Eheim 1250 is what I'd personally call a low-moderate noise pump. Not quiet at all, but generally bearable. The Laing D4's whine drills through my brain like a dentist's drill if they aren't inside an enclosure of some moderate-good amount of sound dampening material. Other people will put them in a case and say that they can't hear them.

It also depends on the level of restriction. The more restriction you put the D4's under with the cooling loop, the louder and more irritating the whine gets.

Cathar-

Where would you place the MCP600/AquaXtreme 50z in relation to the Eheim 1250 and D4 at 12v and 13.8v in terms of noise?

Well my 1250 is what I call "quiet" - it's sat on about an inch of packing foam (fairly firm stuff, the pump barely dents it), without the foam the vibration rumble on the desk is quite loud. Currently I can't hear them pump over the HDDs and radiator fan (can barely hear it with comp off in fact), that's how I'd like to keep it.
HDDs are 2x HGST Deskstar 7k250 80GB SATA drives, rated 26dB idle.
Fan is a comair rotron major DC rated 55dB at full speed, I run it at 10-11V (nominal is 24) so unsure what noise level it is, louder than the HDDs, maybe low 30s dB.

Sounds like the D4 may be a bit loud for my liking as standard. Is overheating likely to be a problem if I were to wrap it in sound damping foam?

MCP600 doesn't get all that much noisier even at 13.8v. My opinion is that the MCP600 sounds much like as if you had 4 or 5 Eheim 1250's running at once (but not vibrating against anything). When inside an enclosed case, the MCP600's noise (a rumbling drone) is generally tolerable if it's not rattling or vibrating anything, but not so if you are targetting super-quiet.

The D4's I personally find to be irritating. Somewhat louder than the MCP600's, but the buzzy square-wave whine is really irritating. However, if you have a few 80mm case fans running at 2500-3000RPM, or 90mm fans running at 2000-2500RPM, then it's about here where you won't significantly notice the D4's noise over the fans if the D4 is inside the case. Also in lower restriction loops, as noted above, the D4's are less noisy.

Super quiet is unrealistic due to the noise of my raditor fan - being a large fan it has a fair amount of bearing rumble so an MCP600 is probably a reasonable noise level for my setup.
My case runs open, so I can't count on a large amount of sound dampening from being inside a case which makes me thing the MCP600 is the one to go for... Now I just have to find where I can get one from. :p

look at the first page of www.procooling.com ;) (the links been there since ive been reading these forums)

Would prefer a more local supplier, or alternatively any non-cooltechnica supplier (had problems with them before).

paul at coolercases might be able to help you out -

www.coolercases.co.uk

they dont stock it, but he will probably know someone who will...

Easy to get the DD-D4 or MCP650 here, but a real pain to find the MCP600. :p

Hmm, I have a spare eheim 1048 here, thinking about trying it in series with the 1250, as I recall as long as total flow doesn't exceed the lower pump's maximum (which seems unlikely) then you can use two mismatched pumps in series without issues. Would give me a look at whether higher flow will actually help.

What rad have you got? I'm not convinced each pump is dumping 25 watts of heat into the system. I know they're rated at 28 watts power consumption, but (correct me if I'm wrong) that doesn't translate into 25 watts of heat going into the water.

I still think 2 x 1250's will offer the best performance / noise which I get the impression is what you're after.

Hmm, I misread the numbers - according to Cathar's data the 1250 only adds about 9W. 2 1250s might be the way to go then.

For rad I run a surplus heatercore, 2-pass, frontal (finned) area is 120x240mm, thickness of 40mm. Fan is a 24V comair rotron Major DC (235cfm max flow, 0.768" h2o max pressure), ducted 70mm from the radiator. Fan usually runs at 12V (current supply is variable 5-16V, planning to change it for a 24V PWM setup).

dtek do them, but only the 1/2" OD version...
http://www.dtekcustoms.com/index.asp...ROD&ProdID=138

Says 1/2" ID on that site, which would be just right...

I was not happy with the muffled D4 whine at all.
Since you already have the 1048 lying around, throw it in the loop and see what you get.

yep 1/2" OD barbs for 1/2" ID tube...

The smallest Iwaki appears to be about the same price as two 1250's. Wouldn't a single pump with similar performance be better overall?

Hmmmmm......

If, according to Cather, the 1250 dumps 9w into the loop and you ran two of them in series... that's 18w being dumped into your loop. I'm too lazy to do the math right now, and I don't know what else is in your loop, but I doubt that that second pump will amount to much more than a .5c degree rise in temperature. Tops. Plus your temperatures might drop with the additional flow. Some people will disagree with me on this next statement: Having a second pump is like RAID 0. If one fails the other will still work. Though statistically speaking the probability of pump failure is doubled, the probability of total loop failure is reduced to half. Food for thought.

I assume you mean RAID 1. RAID 0 is no redundancy, if one drive fails, its all over. Also, if you want numbers on it, look at the pumps thread here or on OCAU, Cathar explores dual pumps with actual numbers