First off Mimium Recommended CPU is T2400 (Core daul) @ 1.8 (NOTE mine is only a 1.6 and works), or a C2d T5600 1.8 (mine is a T6400). For more insight into what others are using that works
http/hardforum.com/showthread.php?t=1463000
If you are having a problem with the laptop display playing the File (.mkv) from the HDD I don't think it is a problem with your CPU speed. As I stated both my laptops are slower (CPU) than yours. My GPUs are both intel with less dedicated Ram. The only Plus on my laptops is (1) Installed Bluray/DVD drive and (2) have swapped the HDD out for an SSD. I would first solve the problem with displaying on the laptop, that may also correct the problem on an external TV Display.
On the laptops, I'm not using any of the software that you are, I use TotalMedia Theatre. On my two desktops, Im using Cyberlink Program (ver 7 and 9) which came free with the two Blu-ray burners. Neither Desktop would be a good comparision as the are both OC to 3.2 GHz.
Guy's he is NOT going to replace his CPU, besides I don't think that is his problem. The fact that he OCed it and it works probably means he is compensating for the real problem. Also many laptops cooling is not set up for Ocing the CPU (may be OK at low usage, but not @ higher CPU utilization NOR do they allow in bios the "Tweek" needed for stability