Do I need/would benefit from a 2nd pump

I have 2 radiators, 2 gpu blocks, a cpu block, res and a pump. My pump is a MCP655 running at max speed. It seems to me my loop is quite populated, would a 2nd pump lower temps any meaningful amount?

My current loop.
http://img813.imageshack.us/i/20810810150539184820077.jpg/

OVerLoRDI said:

I have 2 radiators, 2 gpu blocks, a cpu block, res and a pump. My pump is a MCP655 running at max speed. It seems to me my loop is quite populated, would a 2nd pump lower temps any meaningful amount?

My current loop.
http://img813.imageshack.us/i/20810810150539184820077.jpg/

Click to expand...

IMHO: You should rearrange your loop to make it more efficient before spending money on a pump that will not yield the results you're hoping for. I recommend changing your loop to follow: PUMP to Large RAD to CPU to small RAD to GPU to GPU to Reservoir return to pump. I would also try changing your GPU to a serial configuration where the water enters one GPU flows through single connection to the other GPU then out the other side.

OVerLoRDI said:

I have 2 radiators, 2 gpu blocks, a cpu block, res and a pump. My pump is a MCP655 running at max speed. It seems to me my loop is quite populated, would a 2nd pump lower temps any meaningful amount?

My current loop.
http://img813.imageshack.us/i/20810810150539184820077.jpg/

Click to expand...

It could, are you having temp issues right now? Also, what sort of blocks/rads are you running in terms of restriction?

Seven7Thirty30 said:

IMHO: You should rearrange your loop to make it more efficient before spending money on a pump that will not yield the results you're hoping for. I recommend changing your loop to follow: PUMP to Large RAD to CPU to small RAD to GPU to GPU to Reservoir return to pump. I would also try changing your GPU to a serial configuration where the water enters one GPU flows through single connection to the other GPU then out the other side.

Click to expand...

I'm meh on rearranging the loop tbh. A bit of extra tubing isn't gonna affect anything (that's the only thing I see wrong). Parallel is better for matched GPU blocks btw...keeps the flow in them even and keeps loop flow higher.

Rearranging the loop could make the system easier to bleed, plus having gravity work with me. Dunno how much of a difference it would make but next time I pull the rig apart I'll give it a shot.

The radiators/blocks I have now are:
Swiftech MCR320-QP
HW Labs Black Ice SR-1 140
EK FC6970
Swiftech Apogee XT

You could proably see a decent (2-5C) gain in temps adding a second d5 in that case...the XT really likes flow

Gravity only effects things when you're filling/bleeding, once it's a sealed loop gravitational effects are nil.

IMO if things are working how they are it's silly to shred it just to add another pump.
Now the next time you already have it apart for cleaning or something is a different story.

Bobnova said:

Gravity only effects things when you're filling/bleeding, once it's a sealed loop gravitational effects are nil.

IMO if things are working how they are it's silly to shred it just to add another pump.
Now the next time you already have it apart for cleaning or something is a different story.

Click to expand...

Yeah I'm thinking more long run. Next big upgrade sort of deal. Right now the loop is definitely working great, besides being a nightmare to bleed and fill.

Having run a pair of MCP-655's for years I wouldn't expect a lot of gain from adding a second pump to your loop. I've tested mine in a few configurations, including turning off one pump, and I have as yet to see even P5 on a single pump make a huge difference, P4.2 seemed sufficient to maintain the same cooling as both pumps running P3.2. Admittedly, this is on a pair of older AMD CPU's (OC'ed Opty's) but I can't think of any block more restrictive than a Storm and I had a pair of those in the loop for years along with an MCW-60 and a heater core - and the non-running pump, of course. The original set-up, running just over a year, were the dual-pumps, two heater cores, the MCW-60, and a single Storm. That loop only required P4 to maintain the temps I had when running both pumps at ~P3.1.

I only ran dual pumps as a kind of RAID1 WC loop, which was never needed - not a hiccup in the 4+ years I had them crunching 24/7 (35,000+ hours). You will get less noise running dual pumps, and if you leave your rig running without attendance for any length of time it certainly does help your peace of mind, but I think performance gains will be a wash.


I would be curious to know what temp difference you have dropping your pump down to P4.5 or so, if you have the time to give it a try?


PS
I think your loop order is fine. I've always leaned toward putting my CPU block(s) right after the pump(s), too.
I can understand what the guys are saying about shortening the loop a hair but you would be adding a rather sharp turn in there as well, if you put the CPU between the rads.

I'm a noob as far as WC goes, but I have fooled around with fluid dynamics a little.

Just looking at the pic of his setup, it looks like the second video card is going to have severe diminished flow. Maybe I don't know what I'm talking about, maybe one of the long time WC guys can explain why it should be ok?

I only say this because water will flow to least resistance, which in this case looks like most of it will flow through the first gpu block, and a little will flow through the second gpu block.

OVerLoRDI, what kind of temps are you getting under load on both of the GPU's?

It's been tested many times. The temps on each card are very very close. In fact some results show better balance of temps. The second card isn't getting the slightly warmer water from the first card if in serial. Parellel also reduces flow restriction a tiny bit throught the loop.

So not an issue.

Temps are 58C and 57C @ 100% load.

I'm probably looking to add another radiator and a 2nd pump. I think with 3 radiators, 3 blocks, a 2nd pump would help.

Whats your load temps with Prime 95 AND heaven benchmark. Both for 30 min.

CPU:
GPUs:

Let us know.

GPUs 58/57C
CPU, 52C

This is with an ambient of about 80F.

Naa, temps are fine. IF your flow rate was too low, it would show up on the CPU temps first. Your temps are way just fine. Adding a rad would help temps IF you want a quiter rig. If you already have quiet fans no need to add more stuff. Rads add a very very small amount of restriction. Pumps also ADD heat to the loop.

All I would suggest is you could split it into two loops. I split mine up to separate GPU from CPU with good results here. But I had the rads to do the switch. See my sig for a current pic. I biased the loops to get more rads for the CPU.

I don't know what the components or overclocks, if any, but if you are using I7 with newer gpus then you could probably add one more 120 rad and see much better returns.