1 - Working out the heatload - ie: how many watts of heat you need to be able to cool.
Max possible Power Consumption = Max possible Heat Output. Go here:
http://www.extreme.outervision.com/psucalculatorlite.jsp
Fill in only the CPU and GPU fields (ie: the fields for those items upon which you intend to mount a waterblock), and the pump field (as your pump dumps heat into the system too). Hit calculate, and knock 38w off the result. What you have left is your heatload. If you want to include chipset cooling, just add another 100w for sake of argument and assume you'll be left with headroom. I recommend googling to find out what kind of overclock folks get with similar stepping CPUs and at what vCore, and completing the "overclock my cpu" field with the relevant details, as heatload gets much higher once you start overclocking it. Leave TDP on 85%**
For GPU overclocking, just add another 60w per card to the final total.
2 - Work out system flowrate
Reference
IMPACT OF TUBING SIZES to decide tubing size.
There are plenty of sticky threads
*on forums around the net* comparing latest blocks, pumps, radiators etc to help you decide which parts you want... or if using a kit, simply select the parts as listed in that kit's description on the Online Store.
Now, use the
Flowrate Estimator to work out what your total liquid flowrate will be based on your selection of blocks etc etc. That'll give you an answer in gallons per minute.
3 - Work out roughly what CFM you need combined with liquid flowrate to cool the radiator adequately.
First, open the relevant graph for your radiator...
*note, you'll have to find your own data for other manufacturer's rads*Take the answer from 1), and plot that on the vertical axis. Take the answer from 2) and plot that on the horizontal. Where the two cross, look for the nearest colored line. Each line represents one of 3 fans at either 12v or 7v.
Pf H = Panaflo FBA12G12-H1A - 105cfm, 6.8mmH2O, 41.5dBA @ 12v (Factory spec)
1212M = Delta WFB1212M - 72.4cfm, 3.4mmH2O, 34dBA @ 12v (Factory spec)
Nexus = Nexus D12SL-12 - 36.8cfm, 22.8dBA @12v (Factory spec)
You should be able to guage approximately what CFM-per-fan you need to be moving thru the radiator from some fudgy guesswork and approximations by dividing the space between the fan's lines into equal increments etc.
4 - Choose your fans
Once you know roughly what kind of CFM per fan you want to be using, you now need to find a fan that will produce that amount within your noise tolerance. Refer to the following data...
Look along the horizontal axis for the CFM you need. Go up til you hit the first line. This is the quietest fan for the job. Now find that fan in the links below... and look at the green line on it's graph. Find your CFM on the horizontal axis, go straight up til you hit the green line. Now go straight across to the right. That's the rpm the fan needs to go at. Now go left from the rpm til you hit the BLUE line, and go straight up. That'll tell you what voltage you need to run that fan on to achieve that rpm, and thus achieve the desired airflow at the lowest noiselevel possible.
Individual-fan cfm vs noise vs rpm vs voltage graphs:
Source:
http://www.xtremesystems.org/forums/showthread.php?t=150261 - check this to see if there are any updates to the above info (eg: more fans added to the list)
Doneskis. Your system should now be capable of returning coolant to [ambient + 10degC] (ish)
If this results in your only choice being fans you consider to be excessively noisy, you can recalculate it settling for a final coolant temp of [ambient + 15degC] (so roughly 5 deg C higher temps all round basically - you always sacrifice temperature for noise and vice-versa... low temp = high noise, high temp = low noise) by substituting the dissipation graph from step 3) above with the one below... but you'll need to use the
Liquid Flow Equivalents converter to convert the answer from 2) into lpm, as I can't be arsed to translate the graph from lpm into gpm (sorry!!).
**100% TDP will only ever be reached by your CPU on one occasion. The ONLY piece of software that is capable of running your CPU at 100% TDP is Intel's TAT (Thermal Analysis Tool). At any other time when your PC is at "full load", it's actually only at 85%(ish) TDP. See http://www.ocforums.com/showthread.php?t=4...tat+power+virus
Bear in mind that this calculation will always be MORE than the heatload you're actually producing due to inefficiencies in power regulation in both the PSU and the mobo etc etc... where the calculator may say "CPU A produces 80w at 85% TDP at stock", in reality, your PC will only probably cause it to create 80% TDP at most due to variances elsewhere on the board... hence doing any testing using a PC for the testrig can be difficult, as the heatload can never be quantified with anything near 100% accuracy.
