New mobo build, mixdown is much slower now

Hi guys, I recently was forced to replace my motherboard. Many years newer, and everything seems to work good except the mixdown is very slow.
-I’ve checked mixdown settings, realtime is off
-checked buffer settings
-cpu meter/disk meter is fine during playback
-latency mon is good
I am wondering if it has to do with BIOS as I have left everything on auto (ASUS Z590 board), and as everything seemed to work I left the power settings alone.
As I kind of like the power throttling on auto… I just haven’t experimented with anything yet.
Does anyone have any experience with this?
Win10 Gigabyte Z590

Could it be the disk controller? Maybe it’s in some legacy/compatibility mode, and you need good Windows drivers for all the chips on the motherboard?

Yes, I was thinking of starting by looking into the CPU throttling features, but I think you might be correct that the issue is with the disks.
I upgraded my MOBO, but used all my old SSD’s/hdd. I just plugged in the SATA connections blindly, so I will have to try and reconnect those.
I am trying to think if there is a test I can do to check the disk transfers, which might not be working at optimum performance right now. Like I said in first post, everything else seems fine, without starting new tests I am not familiar with.
I looked through bios settings and nothing seemed to suggest an answer forthrightly.

My second thought is could it be the m.2 drive location, which is the new OS drive (3 slots to choose from) and is my first experience with M.2