Low GPH is better than high GPH?

So i've been looking at different pumps and it came across that 12v is better than Eheim 1250 , and the GPH for a 12v is1.54 GPM (350 l/h) at 12 Volts, and the Eheim 150 Pump output 1200 l/h (317 U.S. gal/hour), but i thought that the more GPH the better it is for cooling, i'm just really confused right now.

I think more GPH would be better. If a car had less water running round it, it would run hotter, i dont know if you can really compair cars to computers, i dont see why not, just electric instead of petrol?!

I have a 12 Volt pump and it really doesnt matter too much as your pump speed because water will transfer the heat at the same rate, your water will heat up at a constant rate. Whats more important is how well you can remove heat from your system, radiator and fans. My load temps never go above 35 with my current settup, just make sure you do the following:
Water should flow from resovoir, to pump, to radiator, to cpu, chipset, video, then back to resovoir. If you have a good radiator its not too important as how many gph you use, as long as the heat is being dissipated into the air.

Cars dont require constant flow. they use thermostatic Valves that open and close based on temperatures. A computer uses an always open system. There is a really big debate on whats better More flow, or less flow. I go with High flow and a high pressure nozzle. But im not a Physisist [sp?]

Flow needs would depend on your block. Some blocks (like the Danger Den ones) like high flow, others like many European blocks like low flow. Here's a few links that really helped me out in making up my mind on what components to get for my WC setup.
http://www.procooling.com/reviews/
http://www.systemcooling.com/mcp350_mod-01.html

all i know....

pumps and their "rated" gph -- have little to do with their actual real world head presssure performance --- i.e. how strong can a pump really pump? (straight up that is)

some pumps with 300gph have small head pressure, where as some with low gph, have high head pressure....

hope that helps!

Well, I achieved my temps with low pressure and 120 mm fan pumping air into
a 300mm radiator.

I feel more comfortable with a low pressure system since there is Less chance of a connection bursting due to pressure.

Either way you go, you can get the job done.

pressure is way more important than flowrate in a water cooling system

pressure is what helps many of the newer blocks based on restrictive jet-impengement technology (Cathar's Cascade/G4/G5 & DangerDen's TDX/RBX), and it also helps when you have a more restrictive system, meaning that you have a larger radiator, more blocks, or both


but if you can reach an equlibrium between flowrate & pressure, that is the PERFECT pump for water cooling - the favorite pump that meets this qualification is the Aquaextreme50z - available @ www.cooltechnica.com for $79 (other options are the DDC/MCP350 & D4/MCP650)

Dont worry about that. Most water blocks are rated at 85psi. Most pumps are rated at 2-4psi

Even going with a 3,000 GPH pump wiht 24 foot head rating (WAY more then any computer cooling setup uses) only runs at 9psi!

Yes, more ACTUAL GPH is better. Each pump is RATED for a certain amount of GPH given no resistance. Once resistance is added (water blocks and heatercores restrict alot), your GPH depends on how strong your pump is (it's head rating). If you scroll down to the bottom of this page, there is a graph of flow rate VS head (the enlarged image I can't get to load at the time I'm writing this), which will give you an idea of how different pumps compare. Which pump is better, sometimes depends on how restrictive your system is.