|BIOS Frequency and Voltage settings (for overclocking)|
|ASRock Z77E-ITX||Asus P8Z77-I Deluxe||EVGA Z77 Stinger||MSI Z77IA-E53|
|Reference Clock||95-150 MHz (0.1 MHz)||80-300 MHz (0.1 MHz)||80-130 MHz (~0.1 MHz)||0-655 MHz (0.1 MHz)|
|CPU Multiplier||14-63x (1x)||16-63x (1x)||16-80x (1x)||16-63x (1x)|
|DRAM Data Rates||1066-3000 (200, 266)||800-3200 (200, 266)||1066-2133 (200, 266)||800-3200 (200, 266)|
|CPU Vcore||0.60-1.70 V (50 mV)||0.80-1.99 V (5 mV)||0.90-1.92 V (1 mV)||0.81-2.16 V (5 mV)|
|CPU VTT||0.98-1.56 V (~6.5 mV)||N/A||0.90-1.53 V (1 mV)||0.95-1.55 V (20 mV)|
|VCCSA||0.93-1.21 V (~18 mV)||0.61-1.56 V (5 mV)||N/A||0.94-1.58 V (20 mV)|
|DRAM Voltage||1.17-1.80 V (5 mV)||1.20-2.135 V (5 mV)||0.90-1.99 V (1 mV)||1.11-2.47 V (7.5 mV)|
|CAS Latency||4-15 Cycles||1-15 Cycles||4-15 Cycles||5-15 Cycles|
|tRCD||3-15 Cycles||1-15 Cycles||4-99 Cycles||4-15 Cycles|
|tRP||3-15 Cycles||1-15 Cycles||4-99 Cycles||4-15 Cycles|
|tRAS||9-63 Cycles||1-255 Cycles||10-63 Cycles||10-40 Cycles|
Though the broadness of each setting varies with each motherboard, all four are capable of exceeding safe and sane voltage levels, or, if you’d prefer, moderate underclocking for reduced energy use. We did encounter one fairly large surprise however.
We've learned to expect 4.6 to 4.7 GHz from this specific Core i7-3770K sample, but that was under Windows 7. With Windows 8, we encountered errors in some services at clock rates greater than 4.5 GHz. The fourth board, EVGA’s Z77 Stinger appears to need a firmware re-work.
Our expected 110 or 111 MHz base clocks are also gone, with the P8Z77-I Deluxe getting closest to our Windows 7 highs under Windows 8. We’ve heard of Windows 8-optimized firmware, but have not, until now, seen any evidence that those optimizations might affect overclocking.
The board with the big voltage regulator, Asus’ P8Z77-I Deluxe also has the highest stable memory data rate. On the other hand, the Z77IA-E53’s third-place memory finish was still good enough to reach our memory’s rated DDR3-2666.
EVGA’s Z77 Stinger reached its top ratio limit, corresponding to DDR3-2133, with less than 1% base clock flexibility, giving it an extra 3 MHz.