You won't find too many benchmarks at 1366x768 because it is rarely used, 1920x1080 is the standard and higher resolutions like 2560x1440 are becoming more popular.
1366x768 means half the pixels of 1920x1080. A GTX 750 Ti can't run ultra settings at 1920x1080 but it will be ok in most games at 1366x768.
Ultra details means big textures however no matter what resolution your screen is. Some new games will require more than 2GB for ultra settings. This would push you up to the GTX 970. This card is much more expensive than the GTX 750 Ti though, and you will need a power supply with two PCI-E power connectors.