8400GS DDR3 can be found in dell 1420, M1330, M1530, compaq presario, HP DV pearl edition
8400GS DDR2 usually found in DElLL 1520 and 1720.
whie so far i nvr heard acer release any GS, but MG series which is using DDR2 in 4720G, same as Z99 asus.
8600GT DDR2 version can be found in all 1520, 1720, M1530. acer 5920G.
i think only XPS M1730, asus G1,2s, toshiba X, macbook have DDR3 version of 8600GT.

so, don't be too fascinated by the 8400/8600/8700 name, the type of memory it's using is very important.

same goes apply to
9500GS - usually DDR2 version in acer, while Asus have 2 version- 9500gs with GDDR3 but not in malaysia.
HD2600- DDR2 found in F5 series asus, F3k
8700M- DDR2 in siemens-fujitsu amilo

really?
but in the customization page, shown there DDR2 only
btw what a shame new dell vostro 1510 only offers 256mb 8400M GS rather than 8600GT

I dun hav a single clue about those.... But for me, I prefer to use the WHQL drivers since they are compatible with everything and lesser headaches to troubleshoot.... To me, drivers won't make ur computer faster so, those so-called tweaked drivers are pretty much useless like the programs that supposed to make ur RAM perform faster....