You might as well just use the pc 133 mem and dump the 125. If you go on Ebay, you an buy pc 133 memory for dirt! I picked up 7 256 mb sticks for $15.
Go there and improve you memory that way and forget about making the pc 133 backward compliant with the 64mb chip. you are just slowing your older puter down using both the sticks anyway.
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.