vince5190 :
I see, so looking at my specs, what do you think is the best VGA for my current system? Due to limited budget, I don't think there's anything I can replace apart from my VGA. What do you guys think of HD 6750?
The 6770 does not require a lot of power; it has a power consumption at full load of around 90W
http://www.guru3d.com/article/asus-radeon-hd-6770-directcu-silent-review/5 Your HD4650 uses about 70W at full load
http://www.guru3d.com/article/his-radeon-hd-4650-512mb-isilence4-review/5 If you're system is running stable with the HD 4650, then I would say that an
HD 6770 upgrade would likely work. You will need a molex to 6-pin PCIe adapter cable to power the 6770; these adapter cables are usually included when you purchase a new video card.
AMD specifies a minimum 500W PSU for the HD4870 with 32A on the 12V rail and (2) PCIe power cables. Your current PSU is not sufficient to run an HD 4870. Although the HD4870 and HD6770 have similar performance capability, the 6770's hardware is two generations newer than the 4870 and requires less power.
BigJ: The 6770 is a re-badged 5770; same hardware, but additional features enabled. Their performance in games will be almost identical.
Edit: PCs use a lot less power than most people think. Please notice that the link to the 6770 review indicated full load power consumption for the rig was 228W. The rest of the system was an overclocked Intel i7 965, 6GB of RAM and this configuration will draw more power than your E7300/2GB of RAM; the rest of the system was similar to yours. Your power draw will not likely exceed the 228W that the review site measured.