The MediaSDK VC-1 decoder is DXVA2 only on Intel GPUs (tested with an i5 and i3), on other GPUs it’s SW only (~15% on my Q6600 + ATI3650).
Now that Sage has there own MKV splitter I’ve been using the ArcSoft TMT2 Video Decoder instead, so I haven’t messed w/ the Intel one for a while.