I upgraded to an NVIDIA GTX Ti 5060 recently as a mid-range choice to ensure my desktop had CUDA compatibility. It's been smooth sailing on my Windows and Linux dual boot system with one problem - performance in the grub console menu was absolutely abysmmal (as in, one motion every few seconds - for both menus and typing).

Lowering the resolution helped but did not solve the problem.

Reading around the advice I saw was to enable "CSM" or "Legacy CSM" mode in the UEFI BIOS.

This completely fixed the problem - the console is now fast as is the console when booted into Linux.