When you write " you have DDR4 ram " do you mean installed in your existing PC or just happen to have some?Lots to unpick there… I’m happy to stay with W10 Pro but it’s whether things like Fusion will continue to work.
@Mark 5 I have DDR4 RAM, so could upgrade the MB and CPU only. Which MB, and how do I know it’ll fit? I bet they’re not standard sizes.
I ask because if you are utilising DDR4 are you sure your CPU and/or MB are not compatible with Win 11?
MBs come in several sizes but for most home PC users, ( including the office ), ATX, Micro-ATX, Mini-ITX , depending on the size of PC case, most will be either be ATX or Micro-ATX, ATX being the largest of the two, you can install Micro ATX inside a PC case that previously had a ATX board but not always the reverse.
Most PC users have Mid-Tower cases, ( not a given ), so either size MB will fit, ' tho you might require some extra mounting lugs which come in 3-4 different lengths, check yours.
Money tight, so determined to stick to a budget I bagged an Amazon bargain, an Asus Tuf B550 with wifi MB, 16 gigs of Corsair ram and a AMD Ryzen 5 4600G, CPU ( the letter G being important to work with my MB choice ).
It's not a high spec' machine, not by any stretch but for my needs, it does me fine, £227 all in but included a USB 3 front hub and a Corsair 550w PSU, ( on a whim ), and some other bits and bobs, that came from another supplier, so not to bad.
I also installed a couple of Noctua case fans but had those already, probably why the PC is so quiet.
Building it, all in all it took me just over an hour so very DIYable and cost effective.
Configuring the ASUS MB bios was something I had to do but more of a steep learning curve for me was converting my existing SSDs partitions from MBR to GPT, required for TMP2, ( I think ), easy I was told, were it 'eck but got there in the end.
So want to reuse older existing SSDs, ( why not ), it's a task that will have to be undertaken.
Belarc Advisor freebie might be a friend here, ( there are others ), it gives you a reasonable idea what's inside your PC and installed, run it--it will generate a report.