Check my power calcs and update please!

littlepuppy · 25 Aug 2010 at 10:28

Am I right in thinking to workout AMPs, I need to divide TDP by 12....

So for 768MB GTX 460's I am looking at

150 / 12 = 12.5 amps

I have 3 of these so 37.5 amps....

CPU is 980x oc'd to 4.2ghz..... What would be the amps on this?

Current PSU is 850AX, is this enough or should I go to 1200 with the option of adding in 1 more card?

850AX can do 70 amps...

This is a folding server BTW.....

Frozennova · 25 Aug 2010 at 10:35

I wouldnt chane it with that amount of hardware, PSU calculator recommends.

600w for a 980x rig with a single GTX470 and so your looking at a 1000w but I would recommend 1200w as a safety net.

Do you have a energy meter (Kill-a-watt) to measure the amount of watts your rig draws at the wall?

littlepuppy · 25 Aug 2010 at 10:57

draws 300 when in full "fold"

Agree mate, im gonna order the 1200, better safe than sorry.

But if I could get away with the 850 that would be best!! lol

Redmint · 25 Aug 2010 at 11:40

http://www.guru3d.com/article/geforce-gtx-460-sli-review/15

I'd extrapolate from that you're probably talking ~700W max draw from your system while folding, although I'm sure someone will try to correct me on that. Also I believe that's the PC power draw so it doesn't take into account the fact the PSU is probably around 80% efficient.

littlepuppy · 25 Aug 2010 at 11:56

Thanks for that... Im staring to think 850 is enough.. Which would be great and save me some cash!

RJC · 25 Aug 2010 at 12:19

850w Will be fine, Andantech show 460 SLI pulls 512w with Fur Mark running and this includes the system as well.

http://www.anandtech.com/show/3810/nvidias-geforce-gtx-460-part-2-the-vendor-cards/8

JonJ678 · 25 Aug 2010 at 12:28

Youre assuming that the components run exclusively on 12v, which they dont. Power / 12 is a reasonable worst case scenario.

Cpu changes considerably when overclocked. Try

Code:

 power = tdp * (vcore/vid)^2 *(frequency / stock frequency)

as an estimate. Folding is hard on components, id want to overspecify the psu and get a single rail one.

Good man, team 10 is lucky to have you

littlepuppy · 25 Aug 2010 at 12:53

sry for being dumb, how do i divide vcore by vid, are they not the same....

Could you demo for my cpu

TDP I think is 130...

Im volts 1.4

Frequency is 27 * 156 - 4212

JonJ678 · 25 Aug 2010 at 22:33

Sorry about that, vid could well mean the same thing as vcore. By vid I meant the vcore when running at stock settings.

Its quite rough-and-ready, but measuring cpu power consumption directly is a bitch.

Assuming it's the 980X, not the Phenom 965,

130 x 1.4 x 1.4 / vid / vid x 4212 / 3330

vid is probably 1.2ish which would give 225W, it'll be a slightly better estimate if you use your chips vid.