The only way to find out would be to measure how far above the connectors the slot is on the riser, then measure the width of the 9800 and see which is more...if the card is wider then its going to hit the other expansion slots... [edit] Please find attached a dodgy diagram
That IS horizontal...you want the gfx card to be parallel to the motherboard right ? Thats the purpose of the riser ? The main thing stopping you is going to be the heatsink and fan (red bit on diagram) on the 9800...If its to wide (Y on the diagram) then its not going to fit. The fan/hs is going to be sitting on the pci slots... Unless I've got it wrong....???
Slightly better diagrams this time ( blue = riser, orange = 9800, red = heatsink, white = pci ) This is what you are trying to do right ? You want the gfx card mounted horizontally, parallel to the motherboard. The problem you will have is there is not enough clearance between the heatsink and the pci slots. If if doesn't actually touch the slots physically, there probably wont be enough air getting to the fan to cool the gpu. Plus I'm pretty sure those cards are heavy, so there may be too much strain on the agp slot and riser card... I think
Hmm I have no idea now...I went back to my voodoo5 to check out the port and its backwards to what I thought it was... I need sleep
so.. where do you want it then? on top of the NB and the CPU? you know there is no room there... unless you are running an old 486 heatsink