power supply purchase help

The only thing I'll add is that I will never buy a regular or semi-modular PSU again. Having a fully modular power supply (the SeaSonic @homerdog recommended above is), is such a pleasure. Only running the cables that you actually need makes all future upgrades of any components so much easier.

 

Yep, bought a new PSU earlier this year. Fully modular Seasonic 760w. It's $109 after MIR on Newegg right now. 80+ Platinum w/7 year warranty.

 

Must be an older model. Now the PRIME series gest 12 (!) years of warranty.

 

Mine isn't a PRIME, it's the model below that. The PRIME seemed like overkill for the price and my uses.

 

Sadly, this one is out of stock on Euro version of Newegg, and they won't/can't say if it'll even be restocked... I'll have a look and see if it is available elsewhere.

Technically yeah, you're totally right, but if you draw 400W on a 800W PSU (not an impossible scenario while say, running Folding@Home on CPU and GPU at same time), then you're right at the peak of the PSU's efficiency curve.

True, true... My older Enermax isn't fully modular; ATX and CPU Aux connectors are soldered-in, as well as one set of PCIe connectors IIRC, but all the other stuff is detachable. Installing that one was still somewhat octopus-ish, so when I bought my current rig's PSU I made sure to get something where every damn cable could detach. My next one will have to be that way as well.

 

400W is pretty much peak efficiency on a 650W PSU like the SSR-650RM.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story3&reid=348

267.9W = 90.0%
332.1W = 90.1%
519.6W = 89.2%

90% is excellent. You'd have to spend a lot more money to do only a slight bit better with respect to efficiency. Not worth it IMO.

 

@Grall It may interest you that I decided to see what would happen if I ran a full 8 thread Prime95 torture test (the max power consumption one) alongside the Furmark GPU torture test. My UPS indicated almost 400W being drawn! Now this is from the wall and power supplies are rated for power delivered - my PSU is like 85% efficient so that's 340W which is still more than I expected to see.

Still, absolute worst case scenario and my 520W PSU is easily within its comfort zone. Even if your system draws 100W more than mine (unlikely) a 650W PSU is right on the money for you.