Do you have the EXACT model number of your card? (should be on the box, or on a decal on the card) XFX I'm sure made more than one 9800GT. Most card makers do! Different versions can have different amounts of memory, different clock speeds, etc.
Also, you really need to fix the title of your thread. That URL for a title is NOT going to get you many responses.
Go to the XFX website here, and scroll down. You'll see NUMEROUS variations of the XFX 9800GT each having their own unique model number.http://xfxforce.com/en-us/products/graphiccards/9series/9800gt.aspx
Their OverView page shows a 128-bit floating point, where as their Specifications page says 256-bit Memory Bandwidth. Is this what you're confusing?