The highest display resolution of the Toshiba C55 is 1366 x 768 pixels. That's 49% less display resolution than the most common display resolution of 1920 x 1080 pixels.
A 1366 x 768 pixels display resolution is in fact the worst display resolution across all laptops that have been on the market for a similar time to the C55.
The best display resolution across similar types of portable PC is 1920 x 1080 pixels.
It may also be worth considering one of the other laptops that have a display resolution of 1366 x 768 pixels currently available including the HP ProBook 645 which has a better Rating.
If the display resolution of this portable PC is not high enough for you then you might also want to consider the HP Pro (1920 x 1080), or the MSI PE70 2QE (1920 x 1080) which is also higher rated.