Wattage requirements

[CNfan21]

I recently bought an EVGA supernova NEX750G 750w 80+ Gold psu for my next build, I thought id buy just 1 r9 290x so it was more than enough, BUT I changed my mind and 2 r9 280x would be WAY better, BUT if i calculate what i have in my build(completed) id reach 739W recommended @100% peak load (from extreme_dot_outervision_dot_com_/_PSUEngine website)(without the "_" and replace the dot by ".")
Would it be enough, I mean theorically it is enough but since id only have 11w loose in my PSU (@100%peak load)?
Im scared to kill my PSU prematurely (even if it has a 10 years GLOBAL warranty on it) but on the other side it will never reach full load, im only gaming on that machine

Here's the final build list:
i5 4670k NOT OC
2x4gb kingston HyperX h2o
Gigabyte g1 sniper z5s
2xAMD radeon r9 280x NOT OC
Intel Intel 730 Series 24gb
3x WD black 1tb(each) in raid 5
EK-DCP 4.0 (12V DC Pump)(for watercooling)
5x120mm fans
4xUSB devices

I used asetek waterchill xtreme pump because it uses the same wattage

[ik9000]

You should be fine on 750w for that. peak loads are unlikely to all coincide at once sfaik plus that 750 rating is sustained RMS not peak. Peak should be higher.


edit yep just checked on the MSI site:http://www.msi.com/power-supply-calculator/

Your recommended minimum power supply is :
Watts!648

The Wattage listed is the maximum peak wattage of each component. The resulted total amount is measured from all devices running at peak utilization. It is important to bear in mind that this amount will never be reached under normal operation.

[kompukare]

If you don't run FurMark both cards while running Prime on the CPU you should be fine. Hexus (test setup: i7-4770K@stock, 16GB, Corsair AX760i, one SSD) got a 225W draw for the complete system in their Sapphire R9-280X review:



Sites like TechPowerUp who measure the power draw of GPU-only, got anything from 298W to 347W (depending on the card) on the R9-280X they reviewed while running Furmark. Running games, the range was a far more reasonable 203W to 244W. (Which basically says that AMD's drivers still don't throttle enough in Furmark compare an Nvidia 780Ti for example: 3D load 269W, Furmark 260W.)

So your supply should be fine.

[kalniel]

Do. Not. Use. Online. PSU. Calculators.

750W is more than enough from a good quality PSU. You'd probably be able to run 2x 290Xs on yours no problem!

[ik9000]

Do. Not. Use. Online. PSU. Calculators.

750W is more than enough from a good quality PSU. You'd probably be able to run 2x 290Xs on yours no problem!

Quite. +1 If I ever win the lottery I will buy a decent UPS supply, and monitoring kit and try running multi GPU rigs from AMD and Nvidia on different power supplies until I find just how low one can go with a PSU before the thing won't actually run properly. That and buying a handful of CPUs and testing the things into the ground with real-usage.

[CNfan21]

thanks a lot guys! Im gonna do what my final plan was, and Im very happy about that!
BTW Im going to use Sapphire's one (probably vapor-X) or the gigabyte's one... not sure yet, but it depends if the waterblock will fit on the sapphire one. or else ill take the gigabyte(they use the same pcb as the reference one)
but again, THANKS alot!

[ik9000]

OCUK were selling the R9 with prefitted water block a while back so I;m sure you should be able to fit one yourself

[Stuen4y]

thanks a lot guys! Im gonna do what my final plan was, and Im very happy about that!
BTW Im going to use Sapphire's one (probably vapor-X) or the gigabyte's one... not sure yet, but it depends if the waterblock will fit on the sapphire one. or else ill take the gigabyte(they use the same pcb as the reference one)
but again, THANKS alot!

Just beware that the die is indented and you need either one of the EK 7970 adapters with a universal water block or a specific block for Tahiti core with the convex on the base to reach the die, if you are still talking about the R9 280X/7970. Bear in mind that the EK adapter does suffer in heat transfer performance due to the double use of thermal compound.