A lot of the performance differences are very hit or miss. with Adobe PS for example, the AMD chip is slower than an i5 3570, but with POV ray, it is nearly on par with the i7 3960X (the $1,000 Intel SB-E offering). As for games, it really depends on the game, though AMD never really scores a real "victory". With Skyrim, for example, the 4770K will net you about a 50fps higher frame rate, while Far Cry 3 (AMD's only real victory that I have found), shows a 2fps lead for AMD. The end result here, is that the i7 tends to be more consistent.
Here is a good place to start: http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/62166-amd-fx-9590-review-piledriver-5ghz.html
As for power supplies, wattage is typically not a number you should focus on - but rather the amperage. Namely to the point that you get the power where you need it most. IE: the 12V rail. Also, you have to watch how they are rated. Many cheaper units, like the ModXtreme, and Cooler Master PSU's, are rated at 25C, an unrealistic temperature. At a normal operating temp of 35C, you lose power. A properly rated unit, like those mentioned above, is rated at either 40C or 50C, and is capable of truly delivering the power you are paying for. Point is, don't go cheap on a power supply when the options are there.
As for performance differences across SSD's. The difference from one modern SSD to the next tends to be about 10~20MB/sec read speeds, and up to 200MB/sec write speeds. Standard spinners hit about 120~150MB/sec read and up to 100MB/sec write speed. A Plextor M3 Pro (What I am using) reads at about 540 MB/sec and writes at about 420MB/sec. The slower version basically cut the write speed in half, and the read speed dropped to 520MB/sec. The thing is, during every day gaming - you cannot tell the difference. I own both drives, and honestly cannot tell the difference. The real gain from spinners, is the access time. Spinners need time to get from one location on the disk to another. SSD's do not.
Laptop: Alienware 14 : Intel i7 4700mq : 8GB ram : Nvidia GTX 765 : 256GB Plextor M3 : 1080P IPS display
Test rig: AMD Phenom X4 955 @ 4.0Ghz : MSI 970A-G46 : 8GB Ram : 128GB Plextor M5s : 2x AMD 5770's (Flashed to 6770) : PC Power and Cooling Silencer 750 : Pioneer BR
Hackintosh : Gigabyte GA-H61m : Intel Celeron @ 3Ghz : 8GB ram : EVGA GTX 550Ti : Patriot Torx 2 64GB : Silverstone Strider ES-50 : OSX Mavericks