most 4X cards will need more current especially if they host a 3D graphics chip. even a RivaTNT with 16 MB could kill the board. the 4X slot provides for more current. If I remember correctly, 2X supports around 6A of current on the AGP slot, while the RivaTNT will need about 9A.
but anyway its left to the board manufacturers to make power traces to the AGP slots.
I killed a ZX board like that. then a BX board. but the Asus V3800 RivaTNT2 M64 with 32 MB works well on the other Asus P2B-F I used, it almost a year now.
so if you want to use a heayduty graphics card on 2X slot, be sure not use its heavy duty.
girish
<font color=blue>die-hard fans don't have heat-sinks!</font color=blue>