On Sun, 21 Feb 1999, Thor Lancelot Simon wrote:

> So, aparrently, there's another issue with the P5A, and AFAICT any
> board using the ALI chipset: only the first 128MB of RAM is cacheable.

Ugh. It took me a while, but I found confirmation on the ASUS web site:

    http://www.asus.com/support/mb/answers/misc/p5a-010.asp

This is mildly annoying, since it didn't mention this in the main
spec. sheet. (Only mildly annoying, because I'm not likely to put
more than 128 MB into this machine, at least not before I replace
the motherboard and CPU.)

> It seems that the ALI Alladdin V chipset has the cache tag RAM built
> onto the chipset (?!), and it's only got enough tag bits for 128MB.

According to http://www25.pair.com/hardware/chipsets/chip-ali-aladdinv.htm,
the chipset it does have some tag ram in the chipset itself:

  Built-in 16K*10 bit SRAM for TAG data to reduce cost and enhance performance
  External Tag RAM free for L2 less than or equal to 512KB
  Cacheable memory up to 512MB with 10-bit Tag SRAM when using 512KB L2 cache
  Cacheable memory up to 1GB when using 256KB L2 cache
  Supports 3.3V/5V SRAMs for Tag Address

However, the motherboard layout diagram in my P5A manual has a chip
marked `tag ram' to the left of the Aladdin chip and below the 512K
L2 cache chip. This is marked `Winbond W24257AJ-8N'. Odd.

cjs
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