The P3's are rated for up to 80 or 90, can't remember, but something much higher than 55. SO if it's stable, it's not really too big a concern. However, it may speed up electronic migration thus speeding up the degredatoin of your CPU and shortening it's lifespan greatly. I used to run my katmai at default w/ the retail hs/fan and their junk thermal paste and my temps are around 50-60's. That's default from Intel!