I've had Gigabyte's "ZXE" MB in its V 1.0 and V 2.0, which equate somewhat to your Asus MB's and I have had both of the VGA cards you named. The largest RAM DIMM that I've had in either one was 256 MB's, and I don't know that was the max it would take. The later KT133A boards were a great deal more flexible, but I don't think there's any difference you'd find with only a Duron 1100 to use (my older one would never treat any XP faster than a 1700 as what it was, no matter the BIOS I flashed it with, it says that a 2100 is a 1500). The TNT VGA blows the ATI Rage card into the weeds badly.