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Pros & Cons of enabline BIOS and video RAM Cacheable?

By stevenbalsillie ·
Can anybody tell me what are the pros and cons of enabling "Video RAM Cacheable" and "System BIOS Cacheable" on my Asus A7N8X Deluxe mainboard?

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No point whatsoever

by GuruOfDos In reply to Pros & Cons of enabline B ...

ROM bios shadowing is of no use to anyone these days! The BIOS rom is used only at boot time. This is why you can boot a PC, then remove the BIOS chip to re-flash a chip from another PC that has been inadvertantly destroyed by flashing an incorrect BIOS program. Under DOS and WIN3.1, BIOS routines were still used under DOS calls to perform disk I/O functions. Shadowing the BIOS to RAM sped up disk based operations under DOS as RAM was often faster than ROM (70 or 60nS as opposed to 120 or 150nS).

Modern OS's only use ROM BIOS routines to initially load bootstrap routines which then loads the OS from disk...then the OS takes over IO access using protected mode drivers, making BIOS INT13 routines un-necessary.

Again, with shadowing Video RAM, in the early days of PC's, video ram was slower than system ram, so shadowing or cacheing video ram sped up the graphics. Modern GPU's use much faster RAM and they use their own AGP-CPU bus which caching has NO effect on.

Unless you are shelling to a legacy DOS application, which actually requires explicit BIOS routines for disk IO (INT 13 Routines) or screen IO (Int 09, Int 21) leave both of these features DISABLED on any OS form Win9x onwards.

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by stevenbalsillie In reply to No point whatsoever

Many thanks. As I'm using a very up-to-date setup running Win XP, I'll do as you suggest.

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