Need a new PSU (probably)

[Fresh Daemon]

So, I just upgraded to voltmodded 7800GTX 512s in SLI. The rest of the rig is fairly modest - a Venice 3000+ with a mild 600MHz overclock, Asus A8N-SLI, 2 SATA hard drives, 2 DVD drives, 5 120mm fans, and watercooling (pump is AC powered and doesn't draw off the PSU).

My existing PSU is an Enermax EG565P-VE. This is a 535W unit with dual 12v rails, 18A on each rail, 34A combined.

After 15-20 minutes of gaming, the computer will shut down. Not reset, reboot, crash, or neatly shut down through Windows, just all power cuts out. I can restart it immediately and it runs fine. I think this is a PSU problem. What's everyone else think?

I am thinking that perhaps the graphics cards are pulling too many amps off of their line, and maybe I should use one PCI-E connector, and power the other through the included 2-molex-1-PCI-E splitter so they draw from separate rails. Is this a stupid idea and if so, why?

The last resort is to get a new PSU. I would like to avoid this if at all possible, as I've just sunk a ton of cash into the rig.

These are some I'm considering:

Fortron FSP 700W (http://www.ncix.com/products/index.php?sku=16679&vpn=FSP700-80GLC&manufacture=FSP%20GROUP%20USA)

Another Fortron FSP 700W (http://www.ncix.com/products/index.php?sku=16843&vpn=FX700-GLN&manufacture=FSP%20GROUP%20USA)

Mushkin 650W (http://www.ncix.com/products/index.php?sku=18245&vpn=550100&manufacture=MUSHKIN)

OCZ GameXStream 700W (http://www.ncix.com/products/index.php?sku=18185&vpn=OCZ700GXSSLI&manufacture=OCZ%20Technology)

As you can see, my budget is up to about $200 Cdn. I think these are decent PSU's, feel free to post your thoughts.

Also, if somebody could concisely explain why there is this argument about one single rail vs. multiple rails, or why quad-rail PSU's are sometimes talked about as being hard to set up?

I have looked for information on this, and have found nothing but one-liner forum posts that don't enlighten at all.

Pardon my lengthy post, but I don't want to leave anything out that might be pertinent.

[Fresh Daemon]

Update after some multimeter testing.

Idle, the 12v line reads 12.13v.
Under full CPU load, it reads 12.10v.
While running F.E.A.R., it reads 11.91v.

This is hooked up to a spare Molex connector. Maybe I should try reading from a PCI-E connector?

This is quite a large sag - 0.22v from idle - but it's still well within ±5% of ATX spec. I didn't get the system to power off in that test.

[perkam]

All you'll ever need: http://www.ncix.com/products/index.php?sku=18184&vpn=OCZ600GXSSLI&manufacture=OCZ%20Technology

Perkam

[Cooper]

Fortron Epsilon 700W and OCZ 700W are totaly the same PSUs (except looks). Go for OCZ - it`s a lot cheaper and would be enough for almost any system

[nn_step]

All you'll ever need: http://www.ncix.com/products/index.php?sku=18184&vpn=OCZ600GXSSLI&manufacture=OCZ%20Technology

Perkam
probably not EVER. but it will do him well for a long while...

[Fresh Daemon]

So, there is no doubt that it's a PSU issue then? Shame.

Fortron Epsilon 700W and OCZ 700W are totaly the same PSUs (except looks). Go for OCZ - it`s a lot cheaper and would be enough for almost any system

The FSP700-80GLC is cheaper, and identical on paper. It's an EPS supply, though, so it would need an 8-pin EPS to 4-pin ATX adapter. These are only a few dollars. Is that advisable? Or would you just go for the GameXStream at about $30 more?

[Praxis1452]

Go for whichever one is cheaper... Btw those psu's at 50C lose around 50W I believe maybe more. Either way it's good enough though. Fortron is good quality choose the cheaper one. The GameXstream does look better..

[Fresh Daemon]

Well, I have a guy who I regularly deal with who has a 700W GameXstream. I'm getting it for $150 CDN. And that should take care of it!

[Silver Bullet]

What about seasonic S12 600W ($149 @ PCcanada), 650W model ETA mid july, but not sure on the price. Otherwise i would go with the OCZ (little more noise, but nice psu).

[Fresh Daemon]

Well, as I say, I'm getting a deal on the OCZ so I think I will go with that. Seasonic is great, but seems to have only 2 12v rails at 18 amps each, which is barely more than my current PSU offers. I can always change out the fan in the OCZ anyway. My rig is getting a little noisy - when I get back from the Philippines in September I will have to get a PA120.3 or something to replace this BIP3.

[Fresh Daemon]

Well, I got the OCZ yesterday and the problem seems solved. I've left the rig running 3DMark loops for hours and no shutdowns or anomalies.