Actually the problem is, I have a Gigabyte GA-78LMT-USB3 motherboard, which does not support DVI or HDMI to VGA conversion. Moreover, I have an LCD monitor at 1366x768 resolution which has only VGA port, neither HDMI nor DVI port. Also, my PSU is 450 Watt. Now, I want to play Tomb Raider (2013), Burnout Paradise etc. games at medium to high settings. Most of the GPUs all you have recommended are very good GPUs, but it would not support my PC unless I upgrade it. I have these games before with an AMD Radeon HD 6450 1 GB, and it has given me quite a good frame rates at low to medium settings. Thus, I want a GPU, preferably AMD Radeon, which has at least one VGA port and also supports my PC, with games playing at medium to high settings.