Stutters and lag in both tty and Xorg

The tty and Xorg stutters every couple seconds. I have a partition with Linux on it where there are no issues like this. I expected OpenBSD to be a bit slower (which I'm fine with for the extra security) but not lag like this.

Specs:

• MSI MPG X670E CARBON
• AMD Ryzen 9 7900X 12-core 24-threads
• AMD Radeon RX 7700 XT
• 64GB of RAM @ 6000MHz
• OpenBSD 7.5

I'm getting these concerning messages in dmesg:

drm:pid0:amdgpu_device_init *ERROR* gpu post error!
drm:pid0:amdgpu_driver_load_kms *ERROR* Fatal error during GPU
init
drm1 detached
amdgpu1 detached
"ATI Raphael" rev 0xc2 at pci24 dev 0 function 0 not configured)

So my suspicion is that my GPU isn't being loaded properly.

I've read that disabling ReBar in the BIOS would help, but it made no difference for me.

I've also run fw_update to ensure that the firmware/drivers are installed:

fw_update: add none; update none; keep amd,amdgpu,vmm

Any help would be greatly appreciated!