I'm having some weird issues with my PC. I'm thinking it could be a power supply issue, but I'm not totally sure. When I boot up my PC, most of the time it will show the BIOS splash screen and then start loading Windows. Recently, however, it sometimes will show the splash screen, then go to a black screen and then shows the splash screen again and then load into Windows. About a year before this booting issue happened I noticed a clicking sound when the machine is running.
If I want to get a new power supply, what brand and size should I get? Here is what is in my PC. I think my current PSU is an UltraX3 800w.
CPU: 2500K OC'd to 4.5GHZ
RAM: 8GB DDR3
HDD: 256GB SSD (OS), 2x - 2TB 5400rpm (Data)
DVD: Blu-ray Writer, DVD/CD Writer
GFX: 2GB GTX670
There are different schools of thought on power supplies, but I always try and get the best one I can afford. Contrary to popular belief, power supply design has progressed quite a bit in the last 3-4 years, and a modern 80+ Gold or 80+ Platinum PSU can run at 300-500W (from a 650-850W rated PSU) with such efficiency and lack of heat output, that the fan will not even turn on at those power draw. A 80+ platinum PSU will save you about $20-$40 a year over a 80+ Bronze, if you leave it on 24/7.
HardOCP, JonnyGuru and the like do a very good in-depth PSU review, which I highly recommend you check reviews for whatever PSU you decide to go with. If your budget will go to $100+, I recommend a
Kingwin Lazer or
Seasonic Platinum. These two companies actually make their own PSUs (or their parent companies do, at least). Corsair and EVGA and the like also
sometimes sell good PSUs, but they buy their PSUs from OEMs (including Seasonic and Kingwin's parent companies) so be sure to check reviews on the
exact model you pick - going from 450W to 650W in the same line could be a completely different PSU from a different company. Given your specs, a very good 650W PSU will be fine. Don't choose a cheapo 800W PSU over a good 80+ Platinum 650W PSU and think you got a 'better' PSU, this is assuredly not the case.
Some of the things you get with a good PSU over a cheap one include low ripple/noise (EM noise in the power line), minimum variation in voltages, and better protection against surges and brown outs. They also tend to be overspecced - i.e. they can actually run 24/7 at their rated wattage or over, without issue, and they last a long time. They are also more efficient, so they save you money over time. Finally, no headaches with 'why did my PC crash?' You know with these PSUs, its unlikely to be because of the PSU.
Oh yeah, and modular PSUs (pluggable power cables) cost more, but reduce case clutter.