The real answer is you change it, run your benchmarks and see if it helped you. It could go either way, so this is one only you can answer for the machine in question.
http://burks.brighton.ac.uk/burks/pcinfo/hardware/bios_sg/bios_sg.htm covers this setting and more.
Why do you ask?
Bob
What are the better settings for these two functions:
"System bios cacheable" and "Video bios cacheable".
Enabled or disabled, and why?

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