How can I get videos to work that require a higher resolution?

Most matroska and mp4 files on my computer only require 704 x 400 resolution. But, there are a few videos that state they require 1280 x 720 and when I try to play these videos, my screen kinda crashes, even if I change my screen resolution to the required size. Has anyone else had similiar problems? Because i'd like to know a way to play these certain files. Thanks in advance.How can I get videos to work that require a higher resolution?
better graphic card. i'm assuming

or convert those files into a lower quality file. kinda what i do. but i use a mac. with isquint. isquint converts any video into mp4, and it gives the option to make the new file high quality or lower. How can I get videos to work that require a higher resolution?
dude u need a new graphic card for ur comp