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Planning for the Future

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realmadrid12

Member
Joined
Jan 17, 2012
Location
Long Island, NY
Ive been trying to figure out what to do regarding my GPU update. I plan on running a 7990 when it comes out. So with that in mind....

My DT is about 4-5 degrees C at idle and at load it goes up to about 8-9 degrees C that is with ambient air at 22C.

I currently have my 1090T, AMD 990 NB, and ram (not that it really affects anything) on my loop which has a 3x120 rad. So I know my temps are pretty much spot on. Ive roughly calculated that my heatload for my current loop is about 325w. And going by the rough idea that a 3x120 rad can support 450w of heat, all my numbers make sense. Yes?

With that said (continuing with that logic)....

If I add a 7990 to the loop, I have roughly calculated the heatload to be 215w per core (taken from a 7970) so that means in total 430w. Now I obviously need more rad. With that thinking that a 3x120 rad supports 450w that would give me 900w (total with GPU is 755w) which is a good amount of head room, but since its all one loop I think I may want more so a 4x120 will give me a total of around a 1075w of rad and give me a better DT.

With that said does my logic make sense? Am I missing anything? Etc? These are all very rough numbers because Im not to sure how to get exact heat loads for my mosfet and NB. But I believe they are fairly close. And If I do go with the 4x120 I should have enough room for some error. And granted my system wont be at 100% all the time.

I got the rad heat loads from here(Post #3): http://www.evga.com/forums/fb.ashx?m=437161

Thanks in advance!
 
Your system will never be at 100% unless you purposefully do so (prime and Heaven).

Also Using formulas for rad capability is cool and all but the issue is Lehpron took the lowest C/W values you can get on the rads which would equate to High RPM loud Fans which i would assume you do not want...

Fan Tests
http://www.xtremesystems.org/forums/...d.php?t=223391
http://www.xtremesystems.org/forums/...d.php?t=261778

WC Data Sites
http://skinneelabs.com/
http://martinsliquidlab.org/

Those sites will get you great fan tests and real world heat dissipation tests.

Flow rate also has a factor in heat dissipation. That said another 120.3 should be adequate for the 7990 and the 1090 since neither will be at full load at the same time.

EDIT: one other thing Lehpron did not take in to consideration is difference in fans (his post is big so its really understandable why he did not) but the 80 CFM fans he tested were in reality probably about 60CFM also without him stating what fans they were we do not know the important stats such as Static pressure and RPM. What I am trying to get at is formulas are cool, and will help, but in order for them to do the work for you there will need to be work done on your end.

Hope i helped a bit.
 
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Well I plan on getting AP-30s as I can turn them down at idle and when I game I use a headset so to be honest they can be as loud as they want at full load.

So basically a 3x rad will be enough, or should I just get the 4x? Money is not a issue and neither is space as I am building my own external mount. Do you think my flow rate would drop to much because of all the blocks? (I have a MCP35X)

Thanks for your help!
 
AP-30's even turned down will still be quite loud at idle. AP-15s would be perfect and cheaper. And if you didnt want to mess with a controller AP-14s are silent at full speed.

as far as 120.3 over 120.4 either will be fine since they will both work. At a heatload of 750W a 120.4 will be better but like i said that one will be up to you.

an MCP35X will do fine. I have mine pushing through CPU, 3 cards, 3 rads and flow is great!
 
AP-30's even turned down will still be quite loud at idle. AP-15s would be perfect and cheaper. And if you didnt want to mess with a controller AP-14s are silent at full speed.

as far as 120.3 over 120.4 either will be fine since they will both work. At a heatload of 750W a 120.4 will be better but like i said that one will be up to you.

an MCP35X will do fine. I have mine pushing through CPU, 3 cards, 3 rads and flow is great!

ok soudns good, Ill take a look at some AP-XX reviews and see which ones I should go with. Ill probably just go with the 4x rad just cause Ill get better temps and I have the room for it anyways.

Glad to know that pump can handle much more than what Im doing now!

Thanks, again for all your help!
 
Not a problem at all.

The main reason i am suggesting the lower speed AP's is because the MCR rads (I assume thats what you have?) are great for low/med speed fans. at 8-12FPI High speed fans do very little in terms of better temps because the rad are already optimized for easy air transfer so it does not take much to push air through.

Now for Blackice rads (20-30FPI) High speed fans will do better and with AP30s there is good static pressure to help that air through.

My main rule with rad fans is (got this from Conundrum): The best way to go is either High Speed/Flow with little Static Pressure, or Low Speed/flow with High Static Pressure.
 
Not a problem at all.

The main reason i am suggesting the lower speed AP's is because the MCR rads (I assume thats what you have?) are great for low/med speed fans. at 8-12FPI High speed fans do very little in terms of better temps because the rad are already optimized for easy air transfer so it does not take much to push air through.

Now for Blackice rads (20-30FPI) High speed fans will do better and with AP30s there is good static pressure to help that air through.

My main rule with rad fans is (got this from Conundrum): The best way to go is either High Speed/Flow with little Static Pressure, or Low Speed/flow with High Static Pressure.

This is the rad I was going to get: http://www.frozencpu.com/products/1..._Slim_Radiator_-_MCR420-XP.html?tl=g30c95s570

It has 20 fpi, and recommended for fans 1200rpms and above so thats why I figured the Higher rpm fans would be better?
 
Well its like i said you can go either way and that will be personal preference. I personally like Silent 24-7 with great cooling, thats why i went with 9 AP-14's because at full speed sitting at my desk I cannot hear them. You may prefer a higher speed 38mm fan that you can turn up and watch your external rad mount fly away! :D

Both will work fine with that rad.
 
I use AP-14s in push/pull on a black ice gtx which is about 20fpi and airfow is fine - it is also pretty quiet. AP-15s sound like they'd be fine for you. not too loud but still great performance. the only problem is actually finding them in stock anywhere.

I too had ap-30's. Even at the slowest speed they'll run on a voltage fan controller they are pretty loud. Convert them to pwm and you may be able to tame them.
 
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