have a question about a power supply

[Josipe]

my sytem is as follows

-ASUS Crosshair III Formula AM3 AMD 790FX ATX AMD Motherboard
-AMD Phenom II X4 955 Black Edition Deneb 3.2GHz (want to overclock to 3.8)
-mushkin 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit
-2 his 4890 vid cards (want to overclock to 950 core/ 1100 mem)
-2 hdd's (western digital black and western digital green)
-5 fans total (3 180mm, 2 120mm)
-1 optical drive
-1 floppy drive

i am considering a
http:///www.newegg.com/Product/Produ...9011&Tpk=850hx

i know that modularity will lower a PSU's capabilities due to the extra electrical resistance it adds. so my question is, will the above listed PSU be sufficient for the overclocked system i have listed above?

[Zero82z]

Modular cables don't decrease a PSU's ability to provide power. And the HX850 is more than enough power for your system. In fact, I'd say it's pretty overkill for your needs. I would generally recommend ~650W for a rig like yours.

[Josipe]

thank you for responding so quickly, the reason why im concerned is because the first 850 watt PSU i had in this system went poof on me and i was just concerned that it may have died due to the stress. i also know that each of the 4890's under full load will draw about 270 watts, thats not overclocked, and the cpu will draw approx 100 - 120 watts under full load, so 270 x 2 + 100-120= 640-660 watts then add in the other components and im guessing under full load it will pretty much push the PSU to its limits. please correct me if im wrong about my cauculations.

[Zero82z]

Each 4890 will draw about 120W under normal load. They won't consume anywhere near 270W of power. Your CPU has a TDP of 125W, so it will draw up to that amount. Your HDs will use about 30-40W, your fans about 20-30W at most, and everything else probably about 50-75W. So in total, you'd be drawing around 450-500W at most with all your hardware at stock speeds. If you plan on overclocking, I'd recommend a 750W PSU, but 850W isn't necessary.

As for your previous PSU, what brand and model was it? It could have been a defect, a random failure, or just a low-quality unit. Unless it was an under-rated PSU though, you wouldn't have been overloading it.

[Josipe]

it was a rosewill extreme 850 watt PSU, four 12 v rails at 20amps each

[Zero82z]

Hmm. Well, those are decent PSUs, so it must have been a defective unit.

[Josipe]

also i did noitce that when my gpus were at full load that i would hear a really annoying high pitch squealing (not fan noise), do u think that had to do with the PSU, MOBO, or the cards themselves

[Zero82z]

Either the PSU, the video cards, or a combination of the two. Squealing isn't really a problem though in most situations. It's annoying, but it doesn't necessarily mean that anything bad is occurring.

[HOOfan_1]

Most likely the cards themselves...although it could have been the PSU...coil whine

[Josipe]

so is the powersupply i have linked above a good choice, or is there another 850 watt supply you would recommend over that one?