Whats the maximum amount of memory that can be fitted?
You can use 256MB memory modules maximum and so the maximum amount of memory is 256×3 = 768MB. You can use combinations of PC100 and PC133 SDRAM and you are still able to use PC133 with all three DIMM slots full (unlike with the Intel 815 chipset). I currently run with a mixture of 2 64MB PC100 CAS 2 sticks and 1 256MB PC133 CAS 2 stick. Always run memory at the highest common speed (so in my case, I max out the PC100 to CAS2). Do not exceed the maximum rated speed of your memory modules.
