Quote from: crumbs on October 22, 2013, 08:08:12 PM

Quote from: MrTeal on October 22, 2013, 07:44:33 PM

Quote from: crumbs on October 22, 2013, 05:15:16 PM

Quote from: DeathAndTaxes on October 21, 2013, 09:47:35 PM

...imagination-based math...
SeaSonic's "X series" for example maxes out at 1250W and a 1250W unit has higher price than a pair of 750W units (1500W total).

SeaSonic X-1250 1250W ATX12V / EPS12V SLI Ready 80 PLUS ...
www.newegg.com ... Power Supplies SeaSonic USA‎
Rating: 4 - ‎1,327 reviews - ‎$254.99 - ‎In stock * 1 = $254.99

SeaSonic X Series X-850 (SS-850KM3 Active PFC F3) 850W ...
www.newegg.com ... Power Supplies SeaSonic USA‎
Rating: 4 - ‎1,327 reviews - ‎$169.99 - ‎In stock * 2 = $339.98

Cypher, your boy can't even count.

Edit: For a list of 1600W power supplies, see here .

All, including Rosewill, are cheaper than a pair of x850s

The LEPA has 4 30A rails and 2 20A rails, with one 20A rail going exclusively to the 24pin connector and another to the 8pin EPS, so it would be a little more of a pain to use than the two single rail X850s. You would not only need to worry about rail balancing, but would need custom adapters (or cutting off cable ends to crimp on PCIe connectors) to get all the power out of it.
The Rosewill unit would be easier with two rails at 110A and 50A, but all the PCIe connectors are on the 110A rail. Again you'd need custom cables. It's also Silver instead of Gold, and costs more than two X850s.
The Coolmax appears to be the same Sirtec design as the Rosewill Hercules (and Scythe Chouriki 2), but I'd want to test that before I chose a unit like that for a machine this expensive.

MrTeal, remember seeing your techy posts. Question for you:

Do you see any potential problems with connecting two separate power supplies in parallel? In other words, connecting the grounds together & the +12 together? I'm not familiar with the regulation/protection circuits on ATX power supplies. Pointers to schematics/datasheets etc. would help too. Thanks.

PS: If you see no problem with bridging two power supplies, i assume you see no problems with bridging all 12V rails on any 1600W power supplies, either. In which case, having custom cables made up seems much easier than some contrived reverse-flow fan mod (according to Cypherdoc, the PSs are exhausting air from the sides of the case, where a standard PS would draw it in).
Thanks for your time.

There shouldn't be any real issues with paralleling the power supplies, especially if they're the same series. It really isn't that much different that paralleling phases in a polyphase supply. The biggest problem you will likely run into is one power supply will be getting them to share the current equally. Paralleling the rails of a multi-rail design likewise isn't a big deal, I've done it myself feeding two different rails into the same GPU.
Getting custom cables made is more of a PITA to parallel things than you probably think it is though. It really is just easier to toss two PSUs in there.

Similarly, there's a huge difference in price and lead time with choosing the stock radiator dimensions that all the closed loop cooler vendors are using vs getting your own thinner and deeper one made. I really don't see an issue with their design, though I don't know why they don't just mount the intake for the PSUs on the inside and then exhaust through the back in typical fashion. Room temperature air has a typical heat capacity of ~34J/(ft^3*K) and a little manipulation gives ~1.75 °C*(ft^3/min)/W. Even if there were dumping 1200W into the case, it would only take ~200cfm to keep the air inside the case 10°C warmer than the outside air. That's well within the operating parameters of any half decent PSU.