Can I use 1/2" and 1/8" tubing for W/C system?

[icewolf69]

Hey all. my new PC is going to be water cooled, and the GPU and CPU block, along with pump and reservoir, etc are all 1/2" fittings. But I'm contemplating getting the OCZ PC2 9200 Ram, which comes stock with a water block with 3/8." Also, most hard drive coolers are 1/8"

So my question is, is it at all possible to have both sizes? i would think it would cut down on water flow quite a bit, but why would someone release peripherals with only 1 size available, especially one so small?

I'm pretty much a water cooled newb, so if someone could explain.

Thanks.

 

[rwaritsdario]

Sure you could but you'll be limited the water going trhu the whole loop. The whole loop will be reduced to the amount of watergoing trhu the smallest tubing size in the loop.
My recommendation would be to cool the CPU and GPU on 1/2" (you can use 7/16" tube for more pressure ) and then, if the memory isnt up for your standards (which I highly doubt it wont be) you make a loop for it alone. Otherwise youll hamper the CPU and GPU too much to be worth it.

 

[cb62fcni]

Yea, I agree, memory has to be clocked pretty high for it to need active cooling. Another option is to get 2 Y splitters with 1 1/2 and 2 3/8 fittings, use one as supply to both RAM modules, and use the other as return. That would allow you to keep everything in one loop without an insane amount of restriction, though it would still add some.

http://www.koolance.com/shop/product_info.php?cPath=62_53&products_id=202

Don't even bother with hard drive coolers, just get a good 120mm fan to blow on 'em and you'll be fine.

 

[rwaritsdario]

Another option is to get 2 Y splitters with 1 1/2 and 2 3/8 fittings, use one as supply to both RAM modules, and use the other as return. That would allow you to keep everything in one loop without an insane amount of restriction, though it would still add some.

Yeah thats a nice idea, but wouldnt he be slipping the pressure in half? Half to the CPU & GPU and half to the memory? It would still come with severe losses to the most important components...

 

[cb62fcni]

Well, I don't know if it would be in half, but of course there would be a pressure hit. What I was proposing is cooling the CPU and then the GPU in series, and then splitting the cooling loop to parallel for the two memory modules, then combining again into series to return to the radiator. It's better than just using a simple reducer and cooling the memory in series if he doesn't want to mess with more than one loop. I would personally set up a second loop like you suggested, but if he doesn't have the money or the room in his case using Y splitters would work just fine. It's not an ideal solution, but it WILL work without a hitch.

 

[rwaritsdario]

Oh I misunderstood you then. Yeah now it seems like a MUCH better idea, since the tubing is 1/2" and the barbs for the memory are 1/4" it, there shouldnt be a loss in pressure.

 

[mr_fnord]

Pressure is factor of rate of flow and diameter, and generally doesn't matter nearly as much as rate of flow for cooling. Shrinking your 1/2" to 7/16" will increase pressure but decrease flow due to friction loss.

Running a serial setup is the easy way to guarantee flow through each cooling block, but it has two possible drawbacks: the circuit length can be longer than parrallel setups, leading to more friction loss and lower flow rates, and you can end up running 'hot' coolant through later components, cooling them less effectively. If your pump is sized large enough, neither will matter, since you'll be pushing several times as much flow as you need. If you have a long series that drops down to a very small size like 1/4" you will be losing flow rate throughout.

In systems that have T's on both the supply and return _before_ you get to a zero pressure dump (the reservoir) _and_ have unequal routes, ie 20" of 1/2 running through the CPU and 20" of 1/4" running through the HDD, you face a much larger problem. The 1/4" might have so much friction loss that the flow through the 1/4" is negligible. This also gets fun to calculate because if you balance the system completely and have all of your pressures perfect, changing any factor anywhere, like replacing a waterblock, shortening any run of hose, corrosion or other resistance buildup in the radiator, the pump wearing in and changing pressure/flow even a few percent can throw it all off again.

A final option is to run all parrallel lines from a block at or near the pump, then size the lines of the run for the flow they will need. So, at the pump you'd have a 1/2" to CPU and GPU, 3/8" to RAM, Ying immediately before and after the modules, and 1/4" to HDD for example. The CPU and GPU would get more fo the flow, then the RAM, and finally your HDD. You can calculate exact flows through each line using a tool like this one:

http://www.efunda.com/formulae/fluids/calc_pipe_friction.cfm#calc

 

[cb62fcni]

Well, I would say that pressure certainly matters, since it is directly proportional to the flow rate. I had been writing assuming a 1/2 to 3/8th T connection, not 1/2 to 1/4, as I thought the RAM had 3/8 fittings. 1/4 shouldn't matter, more restrictive certainly, but with the loop being parallel through the RAM the losses of flow rate due to restriction may be slightly higher, but so long as the pump is adequate it should not nearly be enough to lead to significant heating of any single component in the look. I hope that icewolf decides to NOT cool the HDD, as this is a waste that comes with precious further restrictions. So we assume roughly 12" of 1/2" from pump discharge to CPU, another 6" or so of 1/2" to the GPU, then only a few inches to the T, followed by roughly equal lengths of 1/4" to the input of the RAM, further equal lengths to the other T from the output of the RAM, and then a few more inches of 1/2" into the Rad and back to the pump.

 

[icewolf69]

Yeah the HDD cooler will be the first i get rid of, i'd rather W/C my ram than my HD. So that just leaves 1/4" and 1/2"

I'll be using a swiftech MCP-655 pump, a Thermochill PA120.3 Radiator, and a Swiftech MCRES-Micro High-Flow Reservoir.

thanks for all your help guys; i appreciate it.