Stock voltage seems to be 1.15 V:
Intel i5 2500K P E R F O R M A N C E
• Release date = Jan 2011
• Cores = 4
• Die size = 216 mm²
• Socket =
LGA 1155
• Frequency = 3.3 GHz
• Lythography = 32 nm
• Transistors = 995 Mio
• Cache = L1: 4x 32KB _ L2: 4x 256KB _ L3: 6MB
• GPU = HD3000 _ 12 PP _ 850 to 1100 Mhz
• Memory support = DDR3 up to 1333 MHz
• Average CPU Mark =
7365
• Vcore = 1.15V ◄──
•
TDP = 95W
However, if you BIOS allows undervolting, I found the following values to be stable:
idle = 0.97 V (default) _ 0.82 V (undervolted)
load = 1.19 V (default) _1.05 V (undervolted)