Phillip Corcoran :
With 1GB video ram, max resolution in 32-bit colour is 1366 x 768 (widescreen).
What ???? -- How would you come up with that --- plenty of systems out there run on 1GB or even 512MB VRAM video cards in 1920x1080 resolutions or even higher using dual monitors.. Just look at the specifications fo reven an ancient Radeon 5450 512MB card which clearly lists it's max resolution as 2560 x 1600 -- so please do not be posting misinformation !
Plus the max resolution that a system can use is usually limited more by the capabilities of the monitor(s) it is running than it is the video card running it.
@OP -- As others have asked what video card and what monitor(s) is the system using and what game(s) and what settings are we talking about -- without knowing this it is impossible to suggest any possible improvements.