Summary: Used this in an inexpensive upgrade of an older system paired with ASUS P5N-D LGA775 Nvidia 750i. Already had the RAM, HD, Graphics card and so on, just wanted a better CPU. This thing did not disappoint. Stays fairly cool and very stable, even slightly overclocked. Allows me to have a secondary computer that is capable of most tasks. It perform admirably on Handbrake, especially considering its age. I believe I paid around $45 for mine.
Summary: I can confirm that this CPU works on the Dell Optiplex 745 MT (It shouldn't be used on Desktop, SF or SFF because of cooling), like on many other posts I found on the internet, other users also says this works with Dell Optiplex 745 MT, although Dell only says Dual Cores are supported. I still have the OLD GPU in this computer, and it still works better than with the old E6300 1.86 Duo Core CPU.