MP4 with subs choppy video

[bring-ass]

Hi, i have looking for a solution everywhere without success, so i need help.

I've been using PMS like 2 years now without problems at all. Always thru ethernet.
MKV, MP4, with subs, TV Series, movies, u name it...

But 3 weeks ago ive upgraded my PC to Windows 8 64x.

After that upgrade, i can stream mkv with subs just great. As u may know TV series alomost always came on MKV, so it works ok.
But now all the MP4 fromat that i normally get from movies, they run ok without subs, but when i play MP4 with subs, its just impossible to watch, it gives choppy/shutter video and audio. Sometimes it stops for like 3 secs thens runs but choppy.

Do someone experienced something like this, is there any solution for this ? explanation?

Ty guys in adv.

[Raptor399]

We try to capture everything we know in the FAQ, so maybe this helps you:

FAQ: How can I fix/reduce stuttering video playback?