re: I would like to check that the Optiplex 790 with Intel Core i5 2500 is compatible with 64 bit Windows 10.  Also if there are any driver updates I need to install, and if there are any gotchas Fresh clean install of Windows 10 64 on 790 is straightforward. No Dell driver download needed.  Done it 6-8 times on this model MT. Works perfectly.  The free Microsoft Windows 10 download media is by default 64 bit when I did it.  Only catch might be activation. I always did Win 10 Pro 64.  Maybe your new install activation will be automatic on line.Even 4 gb is good enough for student work.  
Hi, I have a Dell Optiplex 790 (SFF) with an Intel i5 2500 which I no longer use, but which a local church would like me to donate to a local kid who needs a PC for home learning during the Covid-19 lockdown.  I have upgraded it to the latest Windows 10 H121 O/S version, no problems, nice clean install getting rid of all the old stuff.  All seems to work nicely, well built piece of kit. However, I want to pass on a genuinely usable PC.  As it is, it is running Windows 10 32 bits and has a mere 4GB of RAM installed (2 sticks of 2GB DDR3).  I would like to upgrade the RAM to 8 GB (either 2 sticks of 4GB or 4 sticks of 2GB, whichever is cheaper).  However, before doing that I would like to check that the Optiplex 790 with Intel Core i5 2500 is compatible with 64 bit Windows 10.  Also if there are any driver updates I need to install, and if there are any gotchas...Also is there anyone I can contact within Dell regarding charitable recycling, etc.?   My begging list might be free support doing these upgrade, also if Dell might be able to rustle up some compatible old sticks of DDR3, perhaps an old SSD?
Optiplex 790 support for 64bit Windows 10