I'm assuming from the original post it wasn't like it when first built. Is it a problem that has developed out of nowhere or was it following any hardware or software changes?
I haven't heard of Solid Gear PSU's or seen them reviewed (other than a few consumer reviews on Amazon etc.) so I'm not sure how good they are. In terms of wattage rating, it is certainly more than enough for your system though.
The Speccy report looks pretty normal really. Temperatures etc. are good as you said.
What I think might be interesting to do is to load up the GPU and see what temperatures are reached, and also to see whether it causes the freeze up problems seen in games to occur. To load up the GPU you can use Furmark Burn In Test. Warning - this program can put extreme loads on the GPU (far more than a normal game) and if it has insufficient cooling may cause it to overheat (105c is the absolute max temperature of the GTX 650 Ti). Be sure to keep an eye on it! The escape key will abort the Burn In Test. BTW Corruption of the image appearing in Furmark tends to indicate a GPU problem.
Download Furmark and install it and the one you want is "Burn In Test".
BTW I have the same motherboard as you, so I know programs like HWmonitor don't report voltages correctly on it so I would suggest opening up Gigabyte System Information Viewer (available if you installed the programs from the motherboard CD). It's started from the Gigabyte App Center in the system tray. It has several modes but one that looks useful is the "Record" function.
This allows you to record voltages, temperatures etc. over a period of time and graphs them, so any dips become obvious. On my system, I see the 12v rail dipping slightly when I go from desktop to 3D (see the yellow line dipping a bit, I loaded a game to test it). Furmark causes it to dip a little more again. But I'm not having instability problems so I think it's OK. I think it would be useful to have this recording at the same time as running Furmark so you can see what the voltages (particularly the 12v voltage) is doing. If it drops down to like 10v or something it would point suspicion in the direction of the PSU..
Edited by jonuk76, 17 September 2014 - 10:13 AM.