I was overclocking for about 2 or 3 months before this started happening. But ever since I started playing more intense games like FarCry3 or Metro on max my mother board started making this beeping noise. At first I thought something was failing and did the whole running around the whole system checking for every little thing. Then I read somewhere check the PSU and check going straight to wall outlet. The crazy thing was it worked my PSU was fine but if I plug my system directly into the wall there's no beeping. Now the problem that scares me is I had my system on a 750W battery backup serge protector. So do I risk running i5 2500k at 4.2Mhz and GTX560ti on 925 Mhz core clock on straight outlet or just say screw the overclock and play it safe with stock everything? The other thing that was confusing when testing to see what the problem was is I did prime95 for over an hour and it didn't beep. Then I did the heaven benchmark and no beeps so must be when everything is working together the extra power is needed.
Graphic Cards: 2 GTX 560 Ti 2GB in sli
Case: Antec Three Hundred Two
SSD: Crucial M4 128GB SATA III
SSD: Munchkin Enhanced Delux 120GB
Hard Drive: HITACHI 500GB
Processor: Intel Core i5-2500K
RAM: CORSAIR Vengeance 8GB
SAMSUNG CD/DVD Burner
Operator: Microsoft Windows 7 Home Premium 64-bit
COOLER MASTER Hyper 212 Plus
PSU: XFX PRO750W XXX Edition Semi-Modular
The beeping is coming from the Battery Backup, not your motherboard. It does that when you exceed the power rating for the UPS. Don't plug your computer straight into the outlet, you have 3 better options.
1) Buy a higher wattage rated UPS
2) Plug your computer into one of the "Surge only"/not battery backed up outlets on the UPS as those usually can pull more power than you can get through the battery outlets
3) Buy a regular surge protector without a UPS/Battery
Oh wow on the cellphone it posted twice smh. But yeah what you suggested actually worked plugged it into the surge protection only slot. Played for an hour or 2 and no beeps at all the beeping started 20 minutes in before so I know it worked with that amount of time thanks.