Hardware acceleration of DVBviewer in Win7?

I am using Windows 7 and latest drivers of HD3450 has been installed as well as the Purecodec.

However, I still can't use hardware acceleration for DVBviewer as CPU usage is bewteen 50% and 60% something...Does anyone know the solution? Thanks in advance
Oh...icic

But one question is that how come the cpu usage of normal channel is the same as the cpu usage of HD channels
也對!