It's not what size/form factor your 745 is. It'll work.  However, if you have a DT or SFF, you need to make sure it's the skinny one that comes with short bracket. [IMAGE] I'm not 100% sure about the fit in a 745 SFF. USFF has no expansion slots for any cards.
Please can anyone tell me that amd radeon hd 7000 graphics card is compatible with dell optiplex 745 or not?  
Graphics card