Folks, excuse my ignorance, I just did my first gaming PC build, I'm learning, but I'm still a rookie. I'm going to upgrade an old 755 for the practice and fun of it. I took it apart, literally not two pieces were together, cleaned everything, then put everything back together. lol  So, I'm confident I can do any upgrades that are possible. It's an Optiplex 755 SFF with windows 10 64bit, so I'm going with 8GB ram (2 x 4), an SSD in place of the old HDD. I wanted to add just a small SSD as a boot drive and keep the HDD for storage, but it is a SFF and that HDD in that big tray with a fan takes up a ton of room. The CPU upgrade is the area I'd appreciate some advice. From what I understand, more CPUs will work than are listed as officially compatible by Dell. If someone could share a link to a list of CPUs that are known to work, beyond the ones listed by Dell, I'd be very appreciative. Any advice is welcome, for that matter. Again, excuse the lack of knowledge and the long post.