RAM question

[jharris]

I recently added a 128MB PC133 stick of memory to my system. I already had two 128MB sticks of PC100 RAM on-board. I placed the faster memory in the last slot.

When I boot up I see the total RAM at 384MB, and when I check CONTROL PANEL|SYSTEM I see 384MB of RAM. However, I recently ran a diagnostic utility that only showed 256MB of RAM installed BUT 384MB of Windows RAM (???). A reference was made to an issue with my BIOS.

I have a Athlon 700MHz CPU (Slot A) on an MSI K7 Pro (MS-6195) MB with three DIMM slots. According to the documentation, the board can support 768MB of PC100 RAM.

My question is, how do I know what is actually available to my system as far as RAM goes? And does anyone have any idea what the difference between System RAM and Windows RAM might be?

The web site I got the diagnostic utility from was pcpitstop (I'm not advertising for them).

Thakns in advance.