System power usage

[Azarathal]

Hey guys, currently using a 500w zalman psu with two hard drives, an i5 2500k @ 4.4ghz 1.34v, 2x4gb ram at 1.5v and a single 6950 2gb.

Looking to add a second 6950 2gb and I'm wondering whether a hx620w would be sufficient?

Cheers, Mikey.

 

[stulid]

http://www.guru3d.com/article/radeon-hd-6950-crossfirex-review/14

A second card requires you to add another ~160 Watts. You need a 650+ Watt power supply unit and if you use it in a high-end system a 800+ to a KiloWatt is recommended especially if you plan on any overclocking.

I think you are boarderline, the i5 2500K setup you have consumes less power than the older socket1366 test system used in this test. Try looking for a 750W PSU.

 

[Azarathal]

Ah okay thanks for the advice.

 

[Socrates470BC]

Bequiet PSU Calculator

Most of these calculators tend to overestimate, but sometimes they can be useful.

This calculator has an expert mode and a quick mode. Interestingly the quick mode version recommended a 630W PSU operating at 99% capacity (when the choice of expandability was NOT chosen) and the Expert mode recommended a 1,000 Watt PSU operating at 68% capacity (when expandability was Chosen)

I would generally feel more comfortable with a PSU operating in the 60% to 80% of capacity.

Of course Stulid is the expert here and he would not steer you wrong. In fact it would be interesting to hear what Stulid has to say about this particular PSU calculator.

Is it any better or worse than other online PSU calculators?

 

[Azarathal]

I'll get a 750w just for peace of mind

 

[olivier renault]

750W is the recommended spec. Although I must say from my experience, it is OTT. As long as the PSU has 4 PCIE connectors, and over or about 650W (most are anyway).