The PSU generates the most noise, before I dampened the pumps in the front they were bad, but now I can't hear them over the PSU. Compared to my last machine (Antec P180 Passive CPU + Chipset cooling only 2 180 fans on low) it's very noisey. It's noy annoyingly loud, but I've been thinking of a quieter PSU in the future. Oh yeah... Guinea Pigs FTW!