How much of a PSU can you actually use?

[Confused Stu]

My XFX 850w Proseries XXX is sweating big time whenever i load up BF3 on two 7950 crossfired @ 925core and a mildy OCed 8350@ 4,4ghz@1,38v after vdroop. Fan are pretty freaking loud and this is all in a so called open bench scenario. Afraid to put that PSU into a case.

I'm surprised by that. My XFX 750 Core copes very happily and quietly with my 2600k @ 4.8GHz @ 1.38V, crossfired 7970s at 1050 core, and all the usual fans, lights, SSDs and HDDs in a PC. My wall meter showed I was only pulling just over 600W when heavily gaming (Crysis 3 and Sleeping Dogs at 5760x1080 for example). Maybe my PSU fan does spin up but the Windforce fan and case fans must drowned it out?

 

[Sliver]

It wasn't misleading at all. He was just throwing a random fact out there.

Im guessing though it would be impossible to actually run a titan at 1.8 V though since they normally run at 1.1625v on turbo? If someone actually did that they would be braver then me (and probably richer)

Well pardon me for being ignorant. I wasn't aware that his statement was essentially hypothetical. Not everyone knows as much as he does about this stuff. Hence the plebs like me being confused.

When he said :

You need 1 x 1200 watt PSU per Titan when your putting 1.8v through the cards!!!

I did some quick math and thought that for Kaapstads 4 titans you would need a 4800W PSU. Nevermind, though, I've ordered my taxi and I'll be grabbing my coat on the way out.

 

[bru]

Well pardon me for being ignorant. I wasn't aware that his statement was essentially hypothetical. Not everyone knows as much as he does about this stuff. Hence the plebs like me being confused.

Don't worry I wouldn't of thought 8 packs comment was hypothetical, after all he hold the 3dmark03 world record and he is OCUK very own master overclocker, if he says you need a 1200w PSU when putting 1.8v through a titan I would be more inclined to believe him than assume it was a flippant comment.
http://hwbot.org/submission/2375761_8_pack_3dmark03_geforce_gtx_titan_229511_marks

 

[spoffle]

Sorry I'm a bit confused with the "at the wall" remark.

So, if I have a power meter device plugged in the wall socket and its reading 790 watt, is my system actually using 632ish because its 80% efficient?

Would this mean I can make the actual power meter go up to around 1050watts ?

Your PSU is drawing 790 watts, but is only supplying 630 odd due to the efficiency. Power supplies are rated at what they can supply rather than what they can draw.

 

[spoffle]

Don't worry I wouldn't have thought 8 packs comment was hypothetical, after all he hold the 3dmark03 world record and he is OCUK very own master overclocker, if he says you need a 1200w PSU when putting 1.8v through a titan I would be more inclined to believe him than assume it was a flippant comment.
http://hwbot.org/submission/2375761_8_pack_3dmark03_geforce_gtx_titan_229511_marks

It probably has more to do with what a 1200w PSU can supply through the 12v rail, as opposed to meaning the Titan would use 1000w+ at 1.8v.

 

[Confused Stu]

As I'm reading this thread after 8 Pack's post, I'm being reminded of the scene in Life of Brian where the followers try to determine Brian's "teachings" from his discarded shoe and gord....