Wow... finally found this forum! The notebookreview forum is no longer around and I was trying to see whether my M6800 can be upgraded again to maybe an RTX3000 or better!
Yes I still have the P5000 in my M6800 and it is working fine in Window 10. It will need to be flashed to the "engineering sample" vBIOS for Windows and does not need it if using Linux.
If you have no other way like me and needs to flash the vBIOS using the M6800, you need to do it under Linux.
Look like the link to my archived post in notebookreview showed how I did it! Wow... brings back memories!