Roberto Safora Romay queries:

"What those 83 Mhz mean'

The "83 Mhz" means 83 megahertz., it is a speed indicator.

Roberto also asks:

"Which are the elementary things to watch when it comes to mix extension
chips on video cards?"

I don't know about video cards, but with RAM, the memory SIMMS need to
be the same size and speed within a memory bank to work.  If you have
mixed and matched, you are probably running into the same problem.

--Sam Smilie