MSI R9 270X Gaming Artifacts Problem

My MSI R9 270X Gaming Artifacting GTA IV,Far Cry 3, No Artifact Dead Island,Max Payne 2,Left 4 Dead 2,
Motherboard:ASUS P5KC
Processor: Intel Q6600 2.4 GHZ
4 GB RAM
PSU: Gigabyte Superb 720 (5 years old)
Vbios version:015.041.000.000.002887

PSU Problem...