I can speak from experience that using a PSU to weak or a poor quality or both can harm components. I had an Athlon II 240 with 4GB RAM and an HD 6450 on a 260w PSU. The HD 6450 went from black to green in 2 months from the heat. Playing Borderlands at 1024x768 on medium settings the GPU was 90°C+ when in game. I was having issues with the CPU reads for temps but it had a fairly sized Passive heatsink that got quite hot as well. Then the PSU crapped out and did do damage.