The Corsair HX1050 produced a fairly typical set of results in this section that fell a little short of the 80 Plus Silver requirements (85%, 88% and 85% efficiency at 20%, 50% and 100% DC loading) following the OCC power supply testing methodology. The OCC power supply testing methodology doesn't exactly replicate the rail loadings and a shortfall of one or two percent isn't unusual so it would be unfair to mark the power supply (or any other that produced similar results) down in this section. Power factor levels are rarely if ever a problem in high end power supplies, especially with a 110VAC supply, and the HX1050 easily kept the level above the required 0.9 mark at 50% DC loading.
As the article says, we're essentially arguing semantics. You bought a much larger PSU than you needed, but it's not going to cost you much in terms of inefficiencies, and it's not going to harm anything.
Weren't you the guy who Crossfired 5850s? Or was that Oleg?
A second GTX 660Ti adds 150w load (max), a GTX 560Ti adds 170w load (max), so my recommendation of a 500-550w would jump to a 650-700w PSU if you go SLI.
People don't need such gigantic PSUs as they think.
Ah, ok, just checking. Someone was running low-end GPUs in Xfire/SLI and disappointed with their performance about a year ago. At least you're using sufficiently powerful cards to see an advantage.
But I don't understand the reasoning--if you end up going 2x 660Ti's, you will pay more, unless you wait for the GTX 700 series come out, when you pick up an obsolete card at a reduced rate. Even then, it's a lot of waiting at half power (in terms of what you can afford) for a marginal amount of savings.
The cheapest 660Ti is about $250, whereas the cheapest GTX 680 is $410, which is about $90 cheaper than two GTX 660Tis *and* unlike SLI, the 680 will always perform much closer to its performance ceiling (SLI is never near 100% efficient in terms of scaling).
Short of a bargain deal on 660Ti's, you'd be better off grabbing a single GTX 680.
I don't know... your numbers just don't add up. The 3750K has a rated TDP of 77w and you are only running a single 660TI which has a rated TDP of 150w for the stock version (77 + 150 = 227). So if you add those numbers up and add a bit of head room for the RAM and the HDDs it still doesn't come close to 500w (from the wall, 455w @ 91% efficiency). So some where/how you have managed to double your power draw. You have either got one hell of an overclock going for both the CPU and VGA or there's something wrong with the PSU.
According to the efficiency curve on the marketing material, the unit reaches peak efficiency at around 420w - 500w and the fans will start increasing RPM at around 60% load. So technically at 43% load, the fan RPM should be flat @ 20db.
I run a HX650 with a W3540, GTX670, 4 * 1.5TB Seagate 7.2K, 1 * 750GB Seagate 7.2K, X25M 160, X25M 80, 330 180, LSI Megaraid controller, and I can't hear my PSU when my machine is under load.
I also have an AX1200, new, that's currently sitting on my desk because I don't see a reason to upgrade (and I am too lazy to redo my cable management as it's a pain with this many components inside the case). I don't have the exact same setup as you but I can get something close if you need me to help you run some power numbers. (spare processors available: 970, 2700K, 3770K)
If the fan is really loud during your load levels it may indicate a bad fan bearing. You may want to look into getting it RMA'ed.
I've never heard any PSU that's audible, even under load.
Google "ATITool noise" and be amazed. Here's a video demonstrating what happens (and is repeatable even on present-day PSUs; issue has nothing to do with PSU brand either):
* PSU actively drawing 500W: »Re: loud corsair HX1050 * System consists of the following, minus one video card: »Re: loud corsair HX1050 * Core i5 is overclocked to 4.3GHz: »Re: loud corsair HX1050 * All the above could explain about a 400-500W draw under full system load given those specs.
My guess is that the issue has nothing to do with PSU load at all, but probably temperature. Many PSUs will increase fan speed based on temperature, read from a thermistor inside the PSU itself.
There's really not much you can do about this other than try to decrease the overall temperature around the area of the PSU, or to purchase a different brand or model of PSU that might have a fan that's less audible (I've tried to warn people here about how loud PCs are getting these days, sigh) or logic circuitry that doesn't kick the fan on a higher speed until a significantly higher temperature than what the HX1050 does.
I'll use this opportunity to state something clear and in bold: do not consider a fanless PSU given what your system consists of. This will only make the situation worse. I've had the pleasure of using one (rated for 450W) and I could not believe how hot they got under normal load (I had to wait about 20 minutes to remove the PSU from the case, else my fingers would have suffered 1st or 2nd degree burns -- no joke). The increase in PSU temperature has a direct and circular effect on temperatures of the case and all components.
Stick with something that has a 120mm or 140mm fan and advertises very low noise. I would recommend trying Antec or Nexus/Nexustek PSUs. You will need to spend a lot of time looking at full specifications, specifically fan noise ratings. I would suggest a 750W or 850W PSU, cease the overclocking, and stick with just one video card/GPU indefinitely.
Hear Hear, Koitsu. Umm, Chambers, what CASE are you using, and what is the air flow setup in it? Blaming a SMPS is highly irregular. You might want to cease building systems for a while unless you build exactly what others here recommend to you, because you just might not have the knack for it, no offense, please, no offense, it just seems you are still having problems than you should have.
I have the same problem with the fan revving up for absolutely no reason, while under low loads and sometimes idle.
The weird thing is that I haven't noticed it happening while under a heavy load, even with my case fans on high and everything heating up.
My guess is it's Corsair's "Hybrid fan technology", where the fan supposedly shuts off while idle or under very low loads when there's little or no heat buildup. Obviously it doesn't work very well.