Antec TruePower Classic series TP-650C 650 W 80 PLUS GOLD Certified Power Supply

Pros: A lesson in PSU buying, for the uninitiated:

Do not buy the biggest and most expensive supply you can find simply because it sounds "right" to have a 750-watt supply in your PC. You're wasting power, creating unnecessary heat, and wasting your money (unless it's for some reason cheaper to get the 'bigger' unit on day X).

In order:

a) know your PC's absolute maximum power draw. For the average "gamer" PC with one mid-level GPU, this is under 300 watts (at the wall; supplies are measured at "actual" draw). I recommend a Kill-a-Watt meter, personally, and Crysis 3 (v-sync off) should do the trick nicely (it crushes both your CPU and GPU[s] like nothing else I've seen [power draw well exceeds even FurMark]).

b) once you've determined this number, multiply it by .9. That is a "give or take" figure of your "actual" power draw, accounting for the inefficiency of this particular model.

c) Divide your actual maximum power draw (measured * .9) by the supply's rated maximum sustainable output (the number you're paying for). What you'll find is the percentage of the PSU that you're actually using at your PC's maximum (which it will rarely ever hit, if you game with v-sync on). If it is higher than ~.75, the PSU is too "small" for your PC and you must go up another hundred watts, re-measure, and re-find the result. If it is lower than ~.75, the power supply is either ideal or far too "big." Frankly, if you're running one GPU, a Truepower 550 is too much for your system (I'd go with the 450, if available when you're making the purchase).

Your goal is for typical draw to be between 50 and 75%...not 20, 30 or 40%, which I'd estimate to be the case for most people buying the 750-watt unit here. Why? PSUs are most efficient, generally speaking, between 50 and 75%. There is absolutely no reason, save for future ability to upgrade, to buy a bigger supply, in the case of a trusted and respected supply such as this one. Even running two 670s (overclocked) and a 2500K at 1.3v (this alone draws close to 140 watts), my maximum, worst-case draw is barely over 500 watts. On average, during gaming, I'm between 250 and 350 watts. Thus, the 650-watt model is the best choice for my "top 1%" system (.76 at maximum vs. .66 with the 750...too big), where even the 550-watt model could be justified, given my *typical* load during gaming. The 750-watt model can't, as it's less efficient at my wattage and as I have no plans to upgrade the GPUs or CPU at any point in the near future (again, if you *know* you're upgrading, go for it...but you're wasting power and money in the meanwhile). Heck, even if I went with two Titans, I wouldn't have to upgrade...I'd simply be running at lower efficiency levels.

As I stated in my prior review, this (650W) supply runs virtually cold even after half an hour at 500 watt draw. Believe me when I tell you that unless your system is tri or quad SLI and you're running an AMD CPU (help you), you simply don't need

Cons: p.s. "SLI certified" means nothing save for rail configuration. One rail is arguably best, but two is OK (I haven't had a shutdown yet due to a rail being exceeded, so the PSU must be "smart" to some extent; each GPU pulls 66 watts from the motherboard, keep in mind...that's 12V1, not 12V2). (Rails are a measure of supposed protection in the event that something in your system blows; theoretically, the separate rail would prevent the other components from "blowing." I have never seen or heard of anything "blowing" in a PC [save for liquid cooler leakage], but that's me.)

Overall Review: p.p.s. these supplies put out close to 100% of rated power at 12 volts. Virtually everything in a PC uses 12V these days, so simply forget about the other voltage ratings...they mean nothing anymore. Act as if all of your draw is 12V, because it almost nearly is.

p.p.s. to the other gentleman who believes that this supply is a fraud of some kind...my (650 watt) supply is barely warm to the touch (I refer to this as "cold") after 30 minutes at 500 watts. Either a) you're lying, b) you don't know what you're doing, or c) your unit is defective. Instead of writing a silly "review" contesting measured efficiency, take appropriate action by starting with a new model (if you're sure you aren't to blame). The difference between "Gold" and "Bronze" running a 250-watt PC is indeed negligible. What were you expecting? At 500 watts, it's significantly more important (though my interest in efficiency is less heat output...and this is definitely noticeably less, in my experience).

Pros: It "sort of" works now

Cons: Cannot power a Z97 board with 4690k, SSD and onboard graphics under load for more than a few hours at stock speed.

System has now become unstable after 7 months of use

Overall Review: Substituting an 8 year old 1600 watt Ultra x3 power supply allows the system to run 8+ hours under 100% CPU load.