This whole rant is because the Micro Center website lists the MSI R9 390 as requiring a 500W PSU and I was too dumb to notice their mistake. The box clearly says 750W PSU required. My bad, sorry.
I am a Nvidia fanboy and I used to have an open mind regarding AMD. Not anymore...
I owned a R9 390 for 2 days before I stopped making excuses for the rotten experience and exchanged it for a GTX 970. I had my heart set on a used 980, I can't afford a 980Ti and the 970 seemed too close to my 2x SLI 660. When SLI functioned I was fine, but too often I was faced with a single 660 with tanked frame rates. I don't upgrade often and when I do, the performance specs have to be nearly double.
I asked @JokerProductions and he suggested the 970 over the 980. The used 980 was $350 but it had 2 8-pin connectors and I had to pass (I only have 6+8 on the PSU). Plus I was sketchy about buying a card on craigslist. Tom's Hardware recommended the R9 390 as the best value card for 1440p. When I checked it at the Micro Center website (I live 10 minutes from the main store in Ohio), I found that they had a deal on an open box R9 390 for only $288! I bought it at 10AM the next day.
At first I discovered that merely uninstalling the Nvidia drivers and utilities prior to switching teams is not enough. I used Guru3D Display Driver Unistaller, then I searched my C:/ drive for nvidia and cleaned the rest manually. The card was flaky, had lockups, weird Windows slowdowns, but no BSOD. I had more crashes in the past 2 days than I have had in a year. I did manage to work for a few hours using Photoshop and that went well. 3Dmark Firestrike ran no problem. More problems happened when I started to game.
Most games had to be re-installed or have the config files deleted to switch from Geforce to Radeon. My favorite game, Bulletstorm, would not work at all with AMD. When games did work, it was really nice. I played Just Cause 3 and DiRT 2 for a while. JC3 does not support SLI. Upgrading from 720p medium at 40 FPS to 60 FPS 1080p ultra looks pretty sweet. The problem was the excessive power draw. My Uninterruptible Power Supply battery backup started beeping a power event warning REALLY LOUD any time I played for more than a few minutes.
Long story short version:
Micro Center website lists the R9 390 required PSU = 500W.
The fine print on the MSI packaging says 750W PSU required.
My PSU is 700W but that was not the main problem, my 685VA 390W UPS was overloaded.
The GTX 970 requires a 500W PSU.
Asus Z97-AR > i5 4690K 4.5Ghz @ 1.25v > 16GB DDR3 1800 > 2x SSD + 2x HDD
My UPS was reported that at idle the System + AMD was drawing 200W and the UPS maxes out at 390W.
Under load the R9 390 pushed my system to 425 Watts! The UPS was fully in the red and beeping.
I turned the GPU to silent mode and reset the motherboard BIOS to default (no o/c) 3.6Ghz @1.0v. I also tried removing every other device from the UPS but that had a minimal effect on power draw. Looking back, the only thing I did not test was plugging the PC right into the wall, but then I couldn't monitor it. I was able to reduce power draw by 50 Watts to 150W at idle (no o/c) and actually had some fun in.
The System + GTX 970 only sips 85W at idle (full o/c) and maxes out at 200W, same as where the R9 idles.
The R9 is a more powerful GPU, but the power inefficiency score is ridiculous ... let's face it.
In Firestrike the - R9 390 scores 10,437 @ 425W, the - GTX 970 scores 9,716 @ 200 Watts.
The R9 is 107% faster but uses 212% more power to do so. That's bad engineering.
Two days later with my motherboard tuned, the 970 used more power. 100W idle and 330W load, a little faster 9875 Firestrike. During the 2nd test the R9 is +6% benchmark score @ +95 Watts compared to my 970.
Compare the benchmark score on the left to the one on the right. The GTX 970 score of 9,716 is more than double the GTX 660 score of 4,363. Comparing the 660 SLI score to the new 970 GPU, 9716 / 7986 = 121% improvement. The step up in quality of look and feel is far more than the numbers can convey.
This is my system with the R9 390. The Geforce looks almost the same.
The R9 is a fine card. It just didn't make sense for me to spend another $300 on a new PSU and UPS in order to see if AMD will ever get their drivers sorted.
The Flip Side: MSI Geforce GTX 970 Gaming 4G.
I'm not just a Nvidia fanboy, I'm an EVGA fanboy. I have owned their cards and motherboards forever. I considered the EVGA SSC, but I liked the look of the MSI card better. After I exchanged the defective Radeon card at Micro Center and installing my new Geforce, I was up and running in 10 minutes. No crashes, no errors, no hiccups that I have to justify as newbie issues. Smooth like butter. I colored the LED on the MSI logo with orange tape. The Geforce is lighter, thinner (The R9 was ~2.5 slots), not as high and lacks a backplate :(
Oh yeah... I thought the coil whine on my GTX 660 was loud. The coil whine on the Radeon was way louder than the 660's and the 970 is much quieter than the 660's. I tried putting the insulated panel back on my be quiet! Silent Base 800, put the 1/4" thick tempered glass over the steel and the R9 390 was still too loud. Even the fans were loud. The same fans are silent on the 970 because they don't have to work as hard.
That's why Nvidia GPU's are the best. They just work.