XFX power supplies

andybird123

andybird123

andybird123

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30 Nov 2011
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anyone have any experience with XFX power supplies?

my thermaltake 1500w is giving me problems, so I'm looking at the 1250w black edition to replace it, I'm steering clear of OCZ based on bad reports over the years but I can't find much on XFX
 
Im running an XFX myself.

I absolutely fail to work out what on earth someone is running that requires such a powerful PSU.

Mine is a 750 running 4xDVDRW + 4xHD + 2x560GTX and XFI Fatality with LiveDrive, all requiring power and its perfect!
 
3930K, 3 Titan's and watercooling components
an overclocked 3930k can pull up to 400watts on it's own

does anyone know how multirail PSU's will tend to work in terms of balancing themselves?
e.g. in reference to the CPU, it can draw power from the ATX and CPU connectors, so in this example, lets say you squeeze every last drop of OC out of your CPU and it wants 400W, the PSU has say 20A on the ATX and 20A on the CPU connector, so will it balance the 400W over both connectors, or will it try to take 300W over the CPU connector and blow the rails protection?

(I've pegged my actual CPU power usage at 200W, so I should be below the 20A in any case, but the seller of the PSU is claiming I've broken the PSU by forcing 400W through the CPU connector)
 
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BuToNz said:
Wait, you being cereal? :p
Click to expand...

the seller of the PSU has thrown some reviews at me that show total system wattage going from 251W at stock to 555W at 4.8-4.9Ghz
in Prime95, so no graphics usage being in there

however, as I say, I've tested my own and I get 175W at Idle and 360-380W at full usage in Prime95, so the CPU itself is only taking about 200W (which is what the motherboard reads as as well)
 
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It probably wont hit 400W. 250W is quite possible (I measured something like that with my old 920), so if really pushing the 3930k - maybe. It won't pull it all through the 8 pin atx wire though, a significant amount comes through the 24 pin wire. This isn't clever balancing by the PSU, it depend on the motherboard.

Multirail powersupplies are normally a single rail with a collection of current limiters to give the multiple rail "safety" feature. You can get real multi rail supplies, but not for the price of an atx psu.

A titan is what, 200W? 250W? Something like that. So while 3 cards and a six core cpu wont hit 1.5kW, it might get over 800W, and andy is sensible enough to leave a safety factor on it.

Oh, and seasonic will make some XFS supplies, but probably not all of them.

edit: re 555W lol

250W at stock? At most 130W of that is the CPU. Increasing to 550W (430W cpu) would be increasing by a factor of x3.3. 3.2GHz to 4.8Ghz is a factor of 1.5 (power linear in frequency). So a factor of 2.2 on voltage. Power goes with square of voltage, so that's 1.5x over stock voltage. Max VID (most sensible choice relative to TDP) is 1.35V, so to get the power consumption up to 550W overall I'd estimate 2V going through the CPU.

I'm fairly sure sending 2V through the CPU would cause bigger problems than the power supply giving up. So it's unlikely the reviewer applied 2V to it.

Summary: I don't think it's possible to draw 430W through a 3930k without taking vcore to somewhere over 1.8V. (130W*(4.8GHz/3.2GHz)*(1.8V/1.35V)^2 = 350W)
 
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^^ my Titan's on stock are drawing 200W each, got the new PSU today so will try again with overclocking to see what they get to

my CPU is a bit of a stinker overclocking wise as well and doesn't like to go over 4.5ghz without heat running away, I can well see them drawing a fair old amount when pushing 5.0ghz which many do get to
 
600W on gpu isn't so bad. Well under the 1250W spec of the thermaltake. But then, it is a thermaltake, and probably can't get anywhere near the label spec.

Yeah, it probably does pull a lot of current. It's not going to be 400W though, even under phase I think 400W would be a challenge
 
that's at stock, so it will push more when I overclock them, speccing the new PSU isn't a problem, I've ordered a 1250W, even allowing for some extra headroom over what I've shown already I can't see it going over 1000W at the wall, so about 900W on the PSU itself, always handy to have a little headroom however

the thermaltake is a seperate issue - it's rated to 1500W but it's causing crashes
V1 and V2 are the ATX and CPU connectors (only) and are rated to 20A each, so 240W or 480W combined, but my PC is not getting anywhere near 480W, but the seller is saying I've caused the problem by putting "a 400W CPU" on a 240W CPU cable

he's also putting the Titan's at 250W each stock and ignoring the fact that I've spread the 2nd one over 2 rails and saying that I'm putting 500W on V3, when it's more like 400W (a bit less when you consider cards also get power from the PCIe bus - and I have an EVGA power boost running off V4 along with the 3rd Titan)

lots of people run up to 1.45-1.5v on water "without problem", though I have no idea and no way of testing a 3930k at 4.8-5.0, however it's irrelevant because I've tested mine and know what it is drawing, and it's no where near 400W
the problem with the link they've thrown at me is that the review doesn't actually say if the measurement was taken at the wall - in which case you can knock 10-20% off of that 555W straight off the top, which would make it more like 444W of total system power, which brings it back to more like maybe 280W for CPU, at the most
 
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