A few peeps have asked me to provide this info in an easily accessible / findable spot so the don't have to remember what thread it is in or take snippets from multiple threads. If ya find it useful, great .... if ya like something better, by all means use what ya comfy with. First off, I did not create any of the test data ... it's just not available in any one place so that's the only real help I can offer..... besides letting the spreadsheet "do the math" for all of us.Step 1 - Heat Load Calculation.a) CPU Load
- For this I usually use this PSU calculator
Plug in ya CPU, anticipated OC and voltage.... hit "overclock my CPU", thatz ya number....for me it was 135 watts. We don't wanna use the total PSU wattage, it accounts for capacitor aging and adds headroom.....just use the "overclock my CPU" subsection where it gives ya the wattage for CPU onlyb) GFX Card Load
- For this I usually use Guru3D.com's Power Consumption Data
Subjective obtained GPU power consumption = ~ 231 Watts
Now I typically shoot for a 25% overclock .... Now at the very least, if ya wanna go 25% faster, ya gonna use at least 25% more power. But I remembered reading at some point that the way some sites recommended estimating OC'd wattage was to take the % speed increase and square it .... so if I wanna go 1.25 times faster, 1.25^2 was 1.56. But that seemed way to much especially w/ today's voltage limits so I usually go with 1.28 - 1.35 for a 25% OC.
231 x 1.28 = 296 watts or 592 watts for two cards.c) RAM
- I don't see any reason to cool RAM unless ya doing LN2 but if that's ya thing, I figure 3 -5 watts per stick based upon the above PSU calculator and and things I have read in various stickies over the years.d) MoBo VRMs and Chipsets
- Martins and most sites I have visited recommend 10 - 20 for each or 20 - 40 total.e) Pumps
- Most peeps forget about this item .... but ya can find the wattage for ya pumps on martins site
Here you will see a max wattage of 51.52 watts for the twin pumps and 46 watts of heat.
Summary: For me it was 135 (CPU) + 592 (GFX) + 20 (MoBo VRMs) + 46 (Pump) = 792 wattsStep 1 - Heat Load Allocation.
Th next step I take is to "guestimate" what portion of the heat load is to be handled by the rads / fans. To my understanding, Martin specifically designed his tests to measure ONLY the cooling provided by the rad and fans.... even thermal radiation from the rad shroud thru the sides is excluded. And don't forget , heat is being radiated by all the tubing, fittings, exposed portions of water blocks and backplates, etc. ..... and not everything hits max load at the same time.
Now I'd like to claim some scientific method or keen insight was used but I basically came up with the numbers based upon reading all of peoples build results here on OCN..... looking at what the numbers said they should have and what they actually had ....and then looking at my own system (six temperature meters installed to measure temps at various points in the loop + ambient and case temps). At the end of the day .... it seemed for the most part, if ya had enough rad / fans to provide about 60% of the calculated heat load, you were doing OK. Now this is for the typical office application / gaming system and a higher number should be used for 24/7 folding, bitcoin mining or other similar uses. Suggestions welcome.
So in my case.... 792 x 60% = 475.2 so I went a lookin for 465 - 500 watts of rad cooling as a minimum
Would like some input here as Im sure 60% is low for a CPU and 60% is high for a GPU but the 60% average seems to work..... anyone who has rad in / out temps..... measured Delta Ts nor other relevant data, please post.Step 3 - Rad Estimation.
All data based upon test results from martins liquid lab
Martin has a great set of data on his site for numerous 360 radiators including the Alphacool ST30, XT45 and UT60 each of which "tops the charts" from 1000 rpm on up. Xtreme systems had comparable data on the Monsta. As I found it difficult to try and convert the 360 to 240 and 480 equivalents each time I sized a system, I made a spreadsheet to "do the math" for me". Now I am by no means suggesting that all the data is, using that technical term from "My Cousin Vinnie" ..... "Dead-on balls accurate". It is however several orders of magnitude better than the "1 per heat producing component" rule of thumb.
The only data here which is "Dead-on balls accurate" is the data for the 360 rads (indicated by gray shading) as that is a direct quote of what is in Martin's charts. And while we all know that a 120 rad will not exactly be 1/3 of a 360, it's certainly the best approximation I can come up with....if we can accept that, then it's not hard to jump to the 240 being 2 x the 120 and a 480 being 4 x the 120. For the 140mm width rads, again, not "dead on balls accurate" but the numbers are a simple surface area allocation....essentially 140 x 140 / 120 x 120..... until we actually have a set of test data to work with on 140mm, it's the best idea I was able to come up with.
The Monsta data came from the xtremesystems site and was allocated in the same manner as above. Finally the fan data came from the results in Martins fan orientation test linked above. And yes, all data is based upon a "High End Cooling System" with a target Delta T of 10C. If your case and or budget can not sustain a system capable of doing 10C, then try the following:-Divide the recommended amount of rad space for a high end system at 10C by 1.5 for a Delta T of 15C for a Mid to High End Cooling System
-Divide the recommended amount of rad space for a high end system at 10C by 2.0 for a Delta T of 20C and Mid Range Cooling System
-Divide the recommended amount of rad space for a high end system at 10C by 2.5 for a Delta T of 25C for a Mid to Entry Level Cooling System
-Divide the recommended amount of rad space for a high end system at 10C by 3.0 for a Delta T of 30C for a Entry Level Cooling System
Again, I sat down to design my loop looking for 60+% of the heat load in push / pull with 1250 rpm fans .... taking that 500 watt target and dividing it by 85 watts (140mm UT60 @ 1250 rpm), it would seem that I'd need about 5 x 140mm worth of Rad which was perfect for the Entrhoo Primo case I had and the numbers said I'd get 64% of my 475 watt target.
But I wanted to see how well I'd do with just one set of fans (53% of load) and I'm doing just fine with a 8.4C delta T at 1200 rpm and case filters removed....and 12-14C with fans capped at 850 rpm and filters back in. At this point, the only reason I think will make me add fans is curiosity. GPUs peak at 39C under Furmark @ 1200 / no filters and 44c with filters and 850 rpm cap. RoG Bench brings the CPU to 74C at 4.6C tho a new BIOS upgrade has currently left that unstable at my original voltages and haven't decided whether to re-tweak or roll back. Adding a 3rd 240mm rad would in push would take me to about 80%
So again, I hope peeps find it useful, and this will give me something to refer to instead of retyping snippets when needed to answer peeps questions.
The resultant spreadsheet has the aforementioned data including:
a) Watts Allocation for 120, 240, 360, 480, 140, 280 and 420 radiators for fan speeds of 1000, 1250, 1400, 1800 and 2200 rpm
b) Heat Load Generator
c) Heal Allocation Table
d) Case Air Flow table
e) Miscellaneous Data
AquacoolEstimator.XLS 38k .XLS file
Please advise of any errors or confusion and I will try and get fixed ASAP.
XSPCEstimator.XLS 33k .XLS file
EKEstimator.XLS 29k .XLS file
SwiftechEstimator.XLS 29k .XLS file
HardwareLabsEstimator.XLS 32k .XLS file