Game crashing after new GPU installation.

[Preston0620]

The other day I received a new Gigabyte GTX 960 G1 graphics card. Before I got this card I had an MSI GTX 750. I uninstalled all the drivers for my old card before removing it. I then installed my new card and clean installed the drivers. My screen blacked out about 5 minutes into playing Fallout 4. After this happens 2-3 times, I realized my CPU was overheating. I used AI Suite II to Change my fan settings and put my computer on Power Saving mode. I am now able to play Fallout for about 10 minutes before it crashes. Luckily the system doesn't crash now, but the game still does. I checked my CPU Temps and they are fine now. My CPU and RAM usage are also fine. My system is not overclocked. What could be the problem?

-I posted this a few hours ago, but now after a couple a minutes of playing FO4, everything shuts down except for green LED on my motherboard. Is this a PSU problem? I'm pretty sure my PSU has more power than needed to power my PC?

Full specs:
Asus M5A99FX PRO R2.0 MOBO
4.0 GHz AMD FX-8350 / Stock cooler..
8GB DDR3 1600
Gigabyte G1 GTX 960 4GB GDDR5
1TB WD Blue HDD
LG Muti optical drive
750W PSU
5 120mm Case Fans.

Thank you.

 

[Tradesman1]

A 750 should be plenty, how old is it and what is the model i.e. I know there are a number of brands and models I won't touch, i.e. the entire CX series from Corsair are made with cheap caps

 

[Preston0620]

A 750 should be plenty, how old is it and what is the model i.e. I know there are a number of brands and models I won't touch, i.e. the entire CX series from Corsair are made with cheap caps

Sadly... When I first build my pc it was on a budget... and I have a CX PSU... funny thing is Corsair had to send me this one because my previous one screwed up. literally had it for 5 months. And I just flipped it fan side up and everything is running smooth again, but fan up is a no go for me.. What kind of PSU should I get? I also wanted to add another 960 and possibly a liquid cooler in the near future.