Seasonic FOCUS GX-750, 750W, 80+ Gold

This is an excellent power supply for a system with one powerful graphics card or two mid-range cards. A lighter system would be better-served by a version of same with lower wattage. FEATURES: The cable layout is like so: 1 x 24-pin motherboard (sheathed) 1 x 4/8-pin CPU (sheathed) 2 x 6/8-pin PCIe (sheathed) 2 x 4 SATA (not sheathed) 1 x 3 molex (not sheathed) 1 x floppy (not sheathed) This is a fully modular power supply. Modularity means that some or all cables are attached separately so you can pick and choose what you need. This feature becomes more important as wattage goes up so you won't obstruct airflow with unused cables. The cable attachment mechanism is nice and chunky; better than flat inserts that put all four wires in line. PERFORMANCE: Fifteen years ago, most power supplies were about 70% efficient: for a 100W load, they'd pull about 140W from the wall. Not anymore. We now have six major PSU ratings: 80 Plus and 80 Plus Bronze, Silver, Gold, Platinum, and Titanium. These correspond to half-load efficiencies of 80%, 85%, 88%, 90%, 92%, and 94%. Efficiencies at 1/5 and 4/5 load are about 4% less than half-load. This unit is Gold-rated, and according to PCPer, meets the 90% efficiency requirement for that certification. There isn't a strong economic argument for efficiency. Relative to a Bronze PSU, the FOCUS saves about $5 a year for a 24/7/365 100W load in most parts of the country. More noticeable is the acoustic difference. Every watt that isn't going into the system needs to be vented from the PSU. Less efficient units require a bigger or faster fan, which makes more noise. The fan in this one doesn't even turn on until a 200W draw and doesn't begin to ramp up until 400W. For the overwhelming majority of systems the overwhelming majority of the time, it'll be completely inaudible. I haven't commented on ripple and other low-level power characteristics, partly because they're exemplary (par for the course for Seasonic), but also because they're irrelevant. Short of a no-brand $15 tin-box special, just about every PSU on a retail shelf is good enough for a modern system if the wattage is adequate. Computers require less power than they ever have (outside of gaming and overclocking) and motherboard power regulation is better than ever. This FOCUS has no bad behaviors under load, but you could put a $30 Corsair in your system with nary a difference. IN SUM: This is an excellent PSU for a system with a serious graphics card, and where noise performance and efficiency are at a premium. It's also rather well-priced like the G-series that preceded it. I've had at least four Seasonic power supplies. None have failed. None have had coil whine or strange fan behaviors that I've seen even on high-end models from other brands. While Seasonic is an OEM for other manufacturers, I believe their own products represent the best they can do. As above, I don't think this level of performance is strictly necessary, but if you're willing to pay for it, you could hardly pick a better PSU. Just run your system by PCPartpicker's excellent power calculator before settling on a wattage.