Well, this does come across as a bit of a trick question. The system being given away has the via K8T800 Pro cipset which obviously supports a HT speed of 1000MHz; however, the question is what is the maximum HT speed of the K8T800 chipset. This is a different chipset and one which, as far as I can see, Via is no longer promoting. It has a maximum (official) Ht speed of 800MHz, although in general it'll support 1000MHz with no difficulty.
If no-one's going to clarify the question then I might as well have a guess anyway, but it seems a bit odd to have a competition advertising a current chipset with a question about an old one....
Rich :¬)