Are you after a dedicated mini-itx case, or a small matx case?
Options in the mini-itx area seem to have stagnated in the last few years (nothing new on the market), the Inwin Chopin and Cougar QBX being the main ones I'm seeing recommended in addition to the Cooler Master NR200 series and the Silverstone SUGOs...
If I had something like this but reliable and with 2 usb ports, I could keep the existing case and just not hook up the existing front usb, which I use. Any good 5.25" drive bay things like this. Searching on amazon I get too many cheap looking ones. I'd like the faster microsd slot reader but it isn't necessary as I have an external one. The ones with esata ports seem interesting too, though I have that as an add-in card already that I use for backups.
The issue I have with cases is that they are meant to be a tower and not meant to be horizontal and have weight on top of them.
I'm a big fan of the Cooler Master NR200, which is a big boy for mITX but it does support at least SOME 3-slot uATX boards by relocating the PSU cage. It's definitely sturdy enough to support real weight on it and can be used in any orientation. It can handle a full size GPU and it has nifty magnetic side panels. Gigabyte even makes a B450 board that supports four DIMMs and fits in that thing.
No external bays on it, though.
I can vouch for the Cooler Master N200 (note the lack of R, this is a microATX tower), I've come across a few in my work and they're solid enough. The metal's a little thin, but it has a nice featureset for a case in its budget segment and it's not super gaudy or flashy. I'm not crazy about them when the Fractal Design Core 1100 exists though -- I've actually used the Fractal for my P4 build, and while it's a little old school (top mounted PSU) and cable management is less than totally elegant in it, I'm very very very impressed by the build quality especially for the price. For less than you can buy an N200 for right now, the Core 1100 is built way, WAY better. If I were to be looking for a case for my main PC right now, say my Phanteks Enthoo Pro spontaneously melted or whatever, this would be what I buy. Especially since I'm using a microATX board right now and have no use for anything that big.
Cooler Master N-whatever or S-whatever are pretty great cases. They've kind of replaced Antec as providers of a generally good if unspectacular chassis. Actual Antec kind of went off the deep end with weird RGB and festishy skeletal styles for everything but the most basic models. IMO the P5 is the last decent Antec chassis.
I'm keeping this case and just buying this: https://www.amazon.com/gp/product/B00UBFXMXG
It will replace all the front ports and seems well reviewed. Problem solved.
I just have to wait for restock of some of these cheap A520M boards.
I did the move in stages.
First I bench tested the new build with a linux usb boot drive.
Then I moved my boot drive to the new SSD and made sure it booted in the old system and windows still activated.
Then I swapped the boards out.
I had some issues getting the mbr disk over to gpt first. So I put the new ssd in and used a windows usb install to create a windows install on it but didn't finish it. I really just wanted it partitioned correctly as macrium reflect doesn't seem to have an easy mbr to gpt converter thing. Seem mini partition wizard does but I don't have a license for that. So once it was partitioned correctly I moved over the two partitions from the main drive. I'm not really sure what the @500MB one is for or if I should have copied that one. But after doing that it wouldn't boot. error code 0xC0000225. I found some instructions online for repairing BCD and winload.efi file for UEFI device. You basically use diskpart to assign a drive letter (Z) to the EFI partition. Then bcdboot c:\windows /s Z: /f ALL. to copy the files over. That fixed the problem but I had two windows entries in the boot menu. I used msconfig to remove the incorrect one.
And it turns out I never enabled the xmp profile for my old system in the bios.
Once it booted with UEFI enabled and a gpt disk, I then swapped the board.
It worked first boot, yay. Made sure to enable the xmp profile this time on the new MB. Windows activated after a bit. It first said servers unavailable and then it let me reactivate.
I then wanted to get the bios updated and was going to use gigabytes's windows app. I tried to install app center and the PC crashed with page fault in non paged area. Uh oh. Continued to do that right after login on restarts. Booted fine in safe mode. I updated the bios from the bios directly. Then it booted fine. There were some notes in the latest bios update about system stability. I removed all the intel software and drivers. I installed the amd drivers. Ran cinebench for 30 minutes and it got up to 90C. That is concerning. I used the stock thermal pad on the stock cooler. I'm considering other coolers but as it is a small 3U type case, they need to be like 110mm. But I'll likely never push it that hard in actual use. I ran memtest86 overnight and all good. So I assume those faults were either that software or some driver or the bios.
Coolers I've identified are Noctua NH-D9L and Thermalright Silver Soul 110. But they are both a bit pricey for this budget build (Board was 39.99, cpu 119.99, ram was 84.99). I might just replace the thermal paste and call it a day.
One annoying thing is it seems to default the display to the HDMI one vs DVI for booting and going into the bios. I couldn't figure out anywhere in the bios to tell it which display to use first or as primary. I use the DVI as my primary.
Most AMD motherboards have a designated USB port for doing firmware updates even when entirely unpopulated by CPU. For years, I've kept a lowest-cost CPU for any platform I support on hand for doing BIOS flashes. AM4 has been particularly bad about this, especially since AMD kept redefining which chipsets would be supported for newer CPUs, so this was news to me. You have to check the specifics for your board, but generally you format a flash drive with FAT32 and put an unzipped BIOS file in the root directory and the board will just take care of the rest on its own.
The process to switch a drive over from MBR to GPT is likewise pretty straightforward. You just run mbr2gpt /convert /n:drivenumberindiskpart.
Definitely check to see what XMP did with your RAM vs its advertised specs as well. Sometimes I've found stability improvements in setting looser timings than the profile says are correct.