I'm building a core i7 gaming pc this weekend with the following setup:
EVGA SLI motherboard
core i7 920 cpu
1 TB WD caviar black HD
nvidia 275 gtx
corsair 1600 ddr3 ram
cooler master HAF case
Would the Antec 750 Earthwatts provie enough power for this i7 pc, with room for mild-moderate overclocking and 1 more gtx video card in SLI mode? I was able to snag one at micro center for $80 yesterday, which is 1/2 the price of the Corsair 750w model there.
Thanks for the feedback. When using Antec's power requirement calculator, I get just under a 700w power supply recommendation - even with sli, overclocking, adding a blu ray player, a few high performance fans, extra pci cards and fan controller. My concern was about the number of amps on each +12v rail (there are 25A) because the 275 video card requires 40A (via two 6 pin connections, which, with my limited knowledge I would guess 2x25A = 50 would be enough) according to its specifications. See links below.
As you can readily see from the chart the power consumption that was actually measured was much lower than recommendations by psu and video card manufacturers. I have additional charts and reports bookmarked which back up the Tom's hardware article. Unfortunately I am not at home right now. I can post the links tonight.
The power supply calculators and the recommendations of video card manufacturers are inflated. The reason the figures are inflated is because people insist on buying cheap, low quality psu's of questionable value. With very few exceptions a high quality 750 watt psu can handle two video cards operating in dual SLI mode. If I remember correctly the GTX 280 series of video cards max out at a combined total of about 389 watts at full load. I'll verify that this evening.
^+1 to both of JohnnyLucky's posts.
As he described, the minimums suggested by video card manufacturers try to account for the people who have Chokemax PSUs in their PCs. Just as an example, ATI recommends a 450W PSU for a 4850, but you can run it on an Earthwatts 380, because the Earthwatts is a good PSU.
Amperage requirements are usually for the total system, not just the video card.
So the earthwatts 750 would be okay for my setup, allowing for room if I decide to overclock? I was close to going out and buying a 1000w psu to leave room for upgrades, but if I don't have to, I'd certainly like to save the $120 it would take to upgrade!
Two GeForce GTX 280 video cards operating in dual SLI mode use a combined total of about 322 watts and 28 amps at full load. The source of the information is the same Tom's Hardware article I mentioned in my previous post.
I had to do some research and discovered the Silverstone ST75F power supply was an older model. I also discovered it was never submitted to NVIDIA for SLI certification. Here's a link to a technical review at jonnyguru.com which suggests the power supply is not high quality: