less than 2 weeks did i brought this computer and today all of sudden after unplugging and replugging in to switch the graphic card, the PSU decided to stop working.
Still no sure what caused it but when i push the power button nothing happen. After a minute or two, the PSU start making squeezing sound(still nothing turning on) and also when i turn the power button (of the PSU) on and off it also make sounds. Lastly just have the cord on, produce heat.
You have not mentioned the make and model number of your current PSU.. Anyway, a good 500 watt model will suffice for your current build.. But since you have the budget and extra power will help with your future upgrades, consider this -
You really do not need 800W PSU for a single 6850. It is also better to get a good quality PSU than a poor quality one with a bigger number on a sticker. Many poor quality PSUs can't even deliver advertized wattage, and even if they can, other characteristics like ripple are really poor.