Where can I find a graphics card for PCI-E 2.0 x16?

Question

Iron

Motherboard GA-EP45-UD3LR
Now vidyuha ATI Radeon HD 4800 Series The
computer began to turn off after half an hour of work
At rest, this temperature shows AIDA64 Extreme

I think I can change the cooler on the vidyukha or the vidyukha itself

Answer 1

Idle temperatures are similar in meaning to the temperature of Mars. It seems that there is a number, but it is absolutely useless here.
The answer to the title is that any PCi-E graphics card will work. PCI-E different versions are compatible with each other.
The answer is in the text - test the iron. If the power supply is the same age as the rest of the iron, the failure of the capacitors is quite likely. It is worth visually inspecting them, plus the capacitors on the motherboard.