after some digging round found out that the chipset is actually based on the below.
Realtek RTD1283 but customised one made for the Xtreamer.
it's got more HD capabilities than the RTD1282 so i would say its more powerful.
edit.
please note the asus uses the less powerful Realtek 1073 chipset
please note the asus uses the less powerful Realtek 1073 chipset
Where did you find this info?