Graphics Card Upgrade Options - Optilex 7040 SFF

I am looking to upgrade my 7040 SFF to a new card. It has been constantly crashing and my IT guy said the r5 340x isn't very well supported. I just got a Gigabyte GTX750ti Low-profile and noticed the fan on it is too big. I don't know why dell put the pci-e so close to the psu instead of just switching the pci and pci-e slots. I have a single slot, low profile 750ti on order but am worried I will run into the same thing. Does anyone have any advice?