Question about monitor resolution capabilities

I have a nview 27" lcd tv that I use as a computer monitor. It's top resolution is 1366X768. It seems that I can play games on even higher resolution, if what I can in the games options is correct. I play games like cod4 and the new cod world at war which have great graphics. My video card is a pci-e geforce 8800gts w/640mb ram. According to these games I have the following resolutions available to me:
1280X720
1440X900
1680X1050

I'm assuming that I can't push the monitor beyond what the manual says it's highest resolution is. However, It does seem to look like it's playing at a higher resolution when I have it set at 1440X900 or 1680X1050, or is it just my imagination?