power supply question

[davegl1234]

Hi,

I am thinking of getting two r 290's in crossfire, and wanted to check my power supply wouldn't cause any issues. Its a corsair ax1200, so I assumed, at first, it would be plenty, but after checking here I am not so sure:

http://extreme.outervision.com/psucalculatorlite.jsp

I have a 5820k cpu, overclocked to 4.4 @1.3v, which uses a lot of power, and according to the above site, would need roughly a 1100 watt psu along with 290's. However, I imagine when I select two 290's here, they assume reference cards, so if I were to get overclocked models, or overclock myself, I'm worried I might need more than that.

Is this calculator inaccurate and i'll obviously be fine, or should I perhaps invest in a new psu, such as the evga 1600w model?

 

[Sith'ari]

According to bit-tech.net the i7-5820K, when overclocked at 4,3 GHz, reaches 339 watt power consumption
http://www.bit-tech.net/hardware/2014/09/03/intel-core-i7-5930k-and-core-i7-5820k-revie/8
if you add 2 R9 290s, which consume >650 watts then we reach total power consumption at 12 V: > 989 watt
According to Jonnyguru review for Corsair AX 1200, at 12 V, it can give up to 1204,8 watt.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=189
So, probably you should be ok, just roughly though

EDIT: of course the power consumption of the 290s cards are varying depending the manufacturer. Asus 290 consumes up to 380 watts while the reference 290 consumes even more!!

 

[Tsumi]

JonnyGuru does not test overload scenarios, the AX1200 can output more than 1200 watts. It can probably do 1300-1400 sustained, though that won't be good for efficiency or lifespan. As I recall, the only group that did overload scenarios was HardwareSecrets, but thy've stopped doing PSU reviews.

That said, 1200 watts is more than sufficient for your system. Most PSU calculators overestimate piwer requirements, especially the one you linked.

Based on that review, actual systen draw was less than 310 watts after factoring in PSU efficiency. Idle was about 110, so actual CPU power draw under load is less than 200 watts overclocked.