@ivooc
Yeah I meant threaded video. I've had the same RetroPie build from version 4.4, its hard to remember all the changes and configurations I've made. I'll try to share once I think of them.
Do you have a fan installed? The temp_soft_limit is 60 by default and will throttle the cpu to 1.2ghz
I increased the soft_limit to 70 and it barely reaches 63 during emulation.
Have you updated retroarch, raspbian, and your cores, since you installed the image?
the firmware, I should search to find out for sure, I think it is updated when you go to retropie config >> configure >> raspbian >> update raspbian(next to install pixel desktop)
It could be a psx_bios, some have higher compatibility, I have quite a few in my folder actually, but I think scph_101 is the highest compatibility and it will be chosen over the others, not to be confused with scph_1001.
As I say that Gran Turismo refuses to work.
I don't know why, but I did update the core since I last played it.