Best setup for radiators in Corsair 900D?

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Oct 12, 2014
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I need to cool one CPU and two GPUs (I've already got brackets n such, I just need advice on the radiator setups) that I plan on overclocking as much as possible. I can choose between a mix of 120, 140, 240, and 280mm rads. I'd like all GPU rads to be the same, in other words only the CPU's rad can be a different size.

For those of you who don't know about the mounting situations in the 900D...
You can fit either...
- 4 120mm rads
- 3 140mm rads
- 2 240mm rads
- 1 280mm rad and 1 140mm rad
(and ofc 1 240mm = 2 120mm, you can switch them out)

I don't want to replace any of the fans in the front or rear of the case with radiators.

What do you suggest I do?
 
Solution
You'd get slightly better performance from using separate radiators for every component but the gain isn't worth the cost of running 3+ pumps with 3+ reservoirs and that mess of tubing. If you want to run a loop for your CPU and a separate one for your GPUs, you'd be well off with a single 480mm for your GPUs and then a smaller rad (like either a 240mm, 280mm or even a 360mm if you want overkill) for the CPU. Mount the CPU radiator at the top in exhaust and mount the 480 for the GPUs in the bottom. This way, you won't have to worry too much about the heat from the radiators being dumped onto the other components and affecting the overall cooling of the system. Something like that is crazy overkill though.

A single 480mm should be...
Why not go for gold with a 480mm rad? I'm pretty sure you can mount at least one 480mm radiator in the basement compartment if you're only using one PSU.

Also, are you doing a dual or single loop? It might be a decent idea to use a massive 480mm radiator in the basement for your GPUs and then a separate loop with whatever mounts to the top for your CPU.
 


So maybe a 480mm on top for the CPU and 480mm on the bottom for the GPUs? Or should I do 2x240mm rads, one for each GPU (UPDATE: there are only 2 GPUs now)?

Simplified question: 2x240mm radiators or 1x480mm?
 
The rule of thumb is that you want 120mmx120mm of radiator space for each component (and you should consider the CPU overclock as a separate component from the CPU at stock) so with an overclocked CPU and two GPUs, you'd want at least 480mm of radiator.

With the 900D, you have a lot of freedom with what to mount and where to mount it so I'd recommend whatever you think looks best to you. I personally like the way the 480mm looks in the bottom compartment.
 


So for 2 GPUs, should I get a single 480mm rad and connect the GPUs together into one loop or one 240mm and a separate loop for each? I don't care about looks, I'm talking performance wise only.
 
You'd get slightly better performance from using separate radiators for every component but the gain isn't worth the cost of running 3+ pumps with 3+ reservoirs and that mess of tubing. If you want to run a loop for your CPU and a separate one for your GPUs, you'd be well off with a single 480mm for your GPUs and then a smaller rad (like either a 240mm, 280mm or even a 360mm if you want overkill) for the CPU. Mount the CPU radiator at the top in exhaust and mount the 480 for the GPUs in the bottom. This way, you won't have to worry too much about the heat from the radiators being dumped onto the other components and affecting the overall cooling of the system. Something like that is crazy overkill though.

A single 480mm should be enough and if you want a little better performance, you'll always have the option of adding in more radiators. You may also want to consider future expansions. With a 480mm, you'd be set for life with the ability to add in additional radiators in different mounting locations whereas with the smaller 240s, your upgrade path would be limited to replacing them with larger radiators instead of keeping them in the loop (unless you don't mind mounting them in a spot where they dump heat back into your system) so they very well could end up going to waste depending on how you plan on upgrading and expanding your system. If you want to add in a third GPU or cool other components like the motherboard and RAM, you can easily add in a second radiator as needed. The Single 480mm radiator is the simpler option and it will be ample for an overclocked CPU and two GPUs.
 
Solution