Hi, I got QubesOS instaled on Two devices.
One laptop and One desktop.
Planning to buy computer for one of my Family members and Don`t want spend a lot of money for hardware.
And after some digging I found this One:
DELL OptiPlex SFF, 7050 i7-6700 16BG DDR4 (max 64GB)
Would be good computer for Qubes ?
Well thank you very much It looks like this computer is on the list.
And almost Every Option is Green, ecept TPM. Only one computer on that list but should be fine, I hope 
OptiPlex plays well with Qubes. I did several of them for my accomplices. I did not do your exact model. Make sure that your BIOS is updated, you do turn on SSD hardware encryption (if possible use another Optiplex to hardware encrypt your SSD). For installation don’t use kernel latest but use boot UEFI. There are a few things with templates. Don’t rush to update! Shut down sys-whonix until your clock is accurate to less that 0.2 seconds… There are so many things. Secure boot does not work with Qubes because they don’t have the key.
bla…bla…bla
I rate my OSes on the Starbucks rating from -10 to 10. A minus rating is toxic. From 2015 Qubes fell from a 6 to a 2 (small concessions/sell-outs. Even when you are pawn, Qubes does not go negative but it does go to 0. You will get pawn many times… triple digits for me. To recommend an OS it needs a rating of 5. Starbucks rating is a consumer grade computer that you install the OS and update at Starbucks. You are ahead already by not having a consumer grade.
I will post some more templates on i2p. If you can get the GPS time template and use a U-BLOX GPS that is very good. U-BLOX is battle tested against NATO and highly recommended by Iran’s drone makers. People on i2p know tha centralized government is organized crime and organized crime families don’t play nice with each other. Currently I have all my Qubes machine frozen except for a testing one. Frozen means no updates or software installs.
If it is like this one I will guess 99% it will work:
You might want a network card instead of the WiFi