Custom Loop Flow: CPU to GPU or GPU to CPU?

[Jayhawk]

If my radiators, pump, and reservoir are at the bottom of my case, do I have the coolant flow up my GPUs to my CPU and back down or have it go all the way up to the CPU and go back down the GPUs? I'm pretty sure it doesn't matter and people just loop it through the CPU first for better CPU cooling, but I just want to be sure.

[Glenwing]

It doesn't matter.  The water doesn't heat up between one component to the next.  The water flows very rapidly, the entire loop is the same temperature.

[Spev]

It doesn't really matter. Just for good measure in my loop I have a rad between each component, but it shouldn't matter,

[Jayhawk]

It doesn't matter.  The water doesn't heat up between one component to the next.  The water flows very rapidly, the entire loop is the same temperature.

I thought that the coolant picked up heat from each component and was then cooled by the radiators. If what you say is true, where does the heat come from if not the CPU and GPU? The pump can't be that hot.

[Peter Vaughan Truslow]

do whatever is the cleanest runs and is easiest. the fluid heats up less than a degree on each pass through the hottest of components. not worth making your loop look messy over.

the fluid is heated up over time from several passes through the whole loop, as it is also cooled over time, not several degrees on one pass through the radiators(in all but the extreme cases)

[Glenwing]

I thought that the coolant picked up heat from each component and was then cooled by the radiators. If what you say is true, where does the heat come from if not the CPU and GPU? The pump can't be that hot.

 

The water picks up heat from each component but it doesn't change temperature dynamically between each component.  It doesn't pick up that much heat before it moves on.  If you measured the temperature of the water before it passes through the CPU, and then again after it exits the CPU, the temperature wouldn't be any different.  The whole loop changes temperature together over time, the order of components doesn't matter.

[SuperPug]

The water picks up heat from each component but it doesn't change temperature dynamically between each component.  It doesn't pick up that much heat before it moves on.  If you measured the temperature of the water before it passes through the CPU, and then again after it exits the CPU, the temperature wouldn't be any different.  The whole loop changes temperature together over time, the order of components doesn't matter.

 

There is a small temperature gradient within a loop. Not relevant for component / rad sequence tho.

[Jayhawk]

do whatever is the cleanest runs and is easiest. the fluid heats up less than a degree on each pass through the hottest of components. not worth making your loop look messy over.

the fluid is heated up over time from several passes through the whole loop, as it is also cooled over time, not several degrees on one pass through the radiators(in all but the extreme cases)

Would two 480 radiators be overkill then? I just want it for the looks and bragging rights really, not to mention that I already modded my case to fit the radiators and already bought them. I'll be cooling a 5930K, unless I win the lottery and get a 5960X, and 3 GPUs, after the R9 390X and Big Daddy Maxwell come out so I can see which is stronger.

[Glenwing]

There is a small temperature gradient within a loop. Not relevant for component / rad sequence tho.

 

Right.  I'm talking in practical terms

[Peter Vaughan Truslow]

Would two 480 radiators be overkill then? I just want it for the looks and bragging rights really, not to mention that I already modded my case to fit the radiators. I'll be cooling a 5930K, unless I win the lottery and get a 5960X, and 3 GPUs, after the R9 390X and Big Daddy Maxwell come out so I can see which is stronger.

two 480 radiators would probably be more than you need, but with three GPUs i wouldn't quite call it a waste if you have the time and the money.

I on the other hand am a broke student so the best I can afford is a H100

[Jayhawk]

Final question if anyone's still around. What's the quietest pump that I could get away with in this loop? It's about 2.5 feet of acrylic to push coolant through and I need a quiet pump. I returned my Koolance 450 because it was stupid loud. The reservoir holds roughly .75 L above where the pump would be if gravity matters and such.