1. A system for testing a video memory reliability of a video card, comprising: an input module capable of activating a testing program comprising an original image file; a data read/write module capable of writing the original image file into the video memory from the testing program, reading the image file data stored in the video memory during the writing process, and storing the read image file data as a new image file; a data processing module capable of calculating hash values of the original and new image files using MD5 (Message-Digest algorithm 5) hash function; a data comparison module capable of comparing hash values of the original and new image files, and outputting a comparison result; and an output module capable of receiving the comparison result, and indicating whether the video card is normal according to the comparison result.