這東西已經討論很多次，下次不要再問了，請善用搜尋功能，G400可不可以上AGP4x，最主要是看序號，還有系統週邊頻率.....

If your model number starts with G4+MM, you have a Matrox G400 MAX (which has the core running at 150MHz, the RAM at 200 and the RAMDAC at 360MHz). If the model number starts with G4+M, you have a 'vanilla' G400, which core runs at 125MHz, it's memory at 166Mhz and the RAMDAC at 300MHz

The next part can either be DH, which stands for Dualhead, or SH, i.e. Singlehead

4A means that your G400 is capable of running it's AGP texture transfer speed at up to 4x, 4 means it can handle up to 2x AGP
32 or 16 is the number of megabytes of RAM on the card
G means it is equipped with SGRAM, DG means it is equipped with SDRAM