AC3filter + DTS + mkv +MPC-HD = skip frames

Hello.
I was wondering if anyone has a solution to my problem. I've searched all over the internet but i haven't found anything.

my problem is:
when i play a HD mkv file which has DTS audio and I'm using AC3 filter, there are occasionally drop frames. The video skips frames.
If I use EVR in MPC, the problem is solved, but I can't use subtitles that way. (so i use EVR custom or madVR)
If i use ffdshow for audio instead of AC3 filter, the problem is solved again.

But i'd like to use AC3 filter (with EVRcustom or madVR) because i'm used to it, and i like its interface.
Does anyone know how can i solve the problem?

i saw someone else here that had the exact opposite problem: he had dropped frames with fffshow, but not with AC3filter.