MCP655 vs MCP35X for high restriction gpu loop, Need advice!

[phallacy]

Hey guys, new here but have the same user id on oc.net. My second pump in my gpu loop recently died and the side effects were that if I used any application remotely requiring GPU power all 4 cards would heat up to 94 C in a few minutes because the water was not moving out of the cards. I diagnosed it as a pump failure after disassembling the loop, cleaning the radiators and blocks and in the process tested the mcp655 by itself and found out that it was barely moving the water. There are also quite a few 45/90 turns and twists and extenders in order to connect all the blocks and radiators.











My question is should I switch to an mcp35x pump since I've read they're better for high restriction loops? The pic below shows how my setup is and where the pump that stopped working was situated. As you can tell, the old pump was pumping up from a radiator as inlet to another radiator. It was working great for the first month or so then all of a sudden while I was playing watch dogs the pump stopped and my computer shut down because the GPUs overheated. The new pump would be in the same location as the one that died unless someone can recommend another spot that would work? Thanks!!

[stren]

How old was it? In general I like to keep pump types the same, that way you can easily swap tops as needed. It may have just been old and tired, but two d5 pumps should handle that kind of setup just fine unless you really have a ton of small radius 90s.

[phallacy]

How old was it? In general I like to keep pump types the same, that way you can easily swap tops as needed. It may have just been old and tired, but two d5 pumps should handle that kind of setup just fine unless you really have a ton of small radius 90s.

Only about a month old, which is very strange and unusual from what I've read, but im 99.9% sure that it is the pump that is causing the problem. I connected a 1L squeeze bottle to some tubing going into the inlet and some tubing from the outlet into my sink. The squeeze bottle was directly above the pump feeding down. Turned it on and even when placed horizontally (not flowing up like in my rig) the water was not flowing out the other end. It's also very noisy.

Depends on what you mean by "a ton" but each inlet outlet in that gpu loop has either a 45 or 90 rotary fitting (some with bitspower extenders or even a snake rotary) on it to make it all connect.

[kolombo]

After cleaning the loop pomp can`t move water ! Try to drain air, if any into the pomp. Can`t see any other problem but this.

[stren]

also did the pump outlet have a 90 degree on it? If so find a way to change that!

[phallacy]

also did the pump outlet have a 90 degree on it? If so find a way to change that!

It was a 45 degree snake rotary with an extender from the radiator to the pump inlet. The mcp655 didn't have fittings or threads but the opening is 1/2" ID which matches my 1/2" ID x 3/4" OD tubing so I just connected the tubing and secured it with a clamp. It did pump 90 degrees up however straight to the 280 rad.