intermittent issues with overheating/freezing`

[willishutch]

So here's my situation: I recently put together a system for my wife to use, built mostly out of spare parts that used to be in my own system before some recent upgrades. The system consists of an FX 9590 on a Gigabyte 990FXA UD5-R5 with an R9 280X from XFX and a EVGA 850 G2 for the PSU all inside a Phanteks Eclipse P400S. The CPU is being cooled by a LEPA Aquachanger 240, with the radiator mounted vertically in the front of the case. Everything is working most of the time, albeit with some relatively high temps in games. After playing something like Fallout 4 for several minutes, both the CPU and GPU report temps in the low 80's in HWMonitor. However, sometimes when the system is left on for a while (and sometimes not that long) the system will just freeze. The screen stays on but the system is completely unresponsive, and desktop apps are visibly halted. Looking into this problem, I found some other people having a similar problem who fixed it by changing some BIOS settings. That was yesterday and so far the random freezing seems to have stopped, but the heat is still an issue. I had most of these components together in another case, with the radiator mounted in the top, a while back, and it was hot, but not like this. I have seen reports of this aio having problems with bubbles in the loop and I was thinking that might be a factor at play in my situation, especially since when the side panel is open I can touch the radiator and one of the hoses is significantly hotter to the touch than the other, and the top of the radiator next to that hose is hotter than the rest of the radiator. I have tried a variety on fan configurations and found the best one to be 2x 120 intake on the top of the case and 1x 120 rear exhaust, with the radiator fans acting as exhaust on the front. However, I think that even this configuration has some significant shortcomings, since the front vents on the case are relatively restrictive and are probably resulting in a significant amount of the exhaust from the radiator being pulled back in, even with the top and bottom vent covers removed from the face plate.

 

Anyway, my main question is whether it would be a good idea to replace the aio, and if so, what would be the best option, given the restrictive front ventilation of the case and the limited placement options elsewhere in the case. I would look into getting a different case, but my wife seems rather attached to this one. I have mainly been looking at the H100i v2 or the H80i v2 from Corsair, but if there are better options, I'm open to suggestions. The consensus seems to be that the larger radiator is more effective, but I was also thinking that the H80, mounted in the rear exhaust slot would help bring down gpu temps as well, and eliminate the feedback loop of hot air from the radiator being mounted in the front. Do you guys think that the H80i v2 could handle an FX 9590 with acceptable temps? Is there something else I could do to try to bring down temps without compromising the aesthetics or dust resistance of the case?