Had the same "beeping" issue with my new system where the system speaker would issue a single beep on an irregular basis. System - P55a UD4, i750, W7 64. In addition, I had slow read speeds using AS SSD @4K from my Crucial SSD (AHCI) which had been fine on my old system.
Both issues were solved when I increased the voltage to my RAM to 1.64 (spec is 1.65 for my OCZ Gold) as this was being under volted at 1.5v. At the same time, I also disabled power saving features CPU EIST, CPU Enhanced Halt & also disabled Performance Enhance (adv memory settings) which was set at Turbo.
Not sure which setting did the trick, but I thought I would post as the beeping has ceased and as a bonus, my SSD read speed has been restored. Once I've established the setting causing the beeps, I'll post again.