Dell Precision Tower 3620

I uploaded the Precision 3620 3420 Tech Guide for you.  I have both.  The 3420 is the 3620's little brother with much of the same specs.  My 3420 is running an E3-1240 V6 not listed in the Tech Guide.  There's a chance the 1230 will work, but I don't know for sure.

As for BIOS, the 3620 might be a little old for Dell to release any new BIOS updates.  However, the latest BIOS will still be on their site.

I don't know what CPU you have now.  So please keep in mind if you update to either mentioned XEON CPU, onboard graphics is lost and a GPU card is required.

Also, check this out on Google.

Thank you very much for the information provided!

You're welcome.  :)