Overclocking, Power And Heat
Though available Core i7 processors are typically limited to around 220 MHz BCLK, a few select samples can at least exceed that limit. Extreme overclockers, especially though with sub-ambient cooling, will also try higher voltage levels than most of us would consider safe. Here’s what the two Micro ATX Core i7 motherboards offer in BIOS.
| BIOS Frequency And Voltage Settings (For Overclocking) | ||
|---|---|---|
| Asus Rampage II Gene | DFI LANParty Jr X58-T3H6 | |
| CPU Base Clock | 100-500 MHz (1 MHz) | 133-250 MHz (1 MHz) |
| CPU Multiplier | Yes | Yes |
| DRAM Data Rates | BCLK x6 - x16 (x2) | BCLK x6 - x16 (x2) |
| PCIe Clock | 100-200 MHz (1 MHz) | 100-250 MHz (1 MHz) |
| CPU Vcore | 0.85-2.50V (6.25mV) | 1.00-2.00V (12.5mV) |
| Uncore Voltage | 1.20-2.50V (6.25mV) | 1.21-1.61V (10mV) |
| IOH Core | 1.11-2.20V (13.25mV) | 1.10-1.45V (50mV) |
| ICH Core | 1.11-2.20V (13.25mV) | 1.05-1.35V (100mV) |
| DRAM Voltage | 1.51-2.50V (13.25mV) | 1.455-2.40V (15mV) |
| CAS Latency | 3-11 Cycles | 1-11 Cycles |
| tRCD | 3-10 Cycles | 1-31 Cycles |
| tRP | 3-10 Cycles | 1-10 Cycles |
| tRAS | 3-31 Cycles | 1-31 Cycles |
While the Rampage II Gene offers a broader range of Bclk and voltage settings, the LANParty Jr X58-T3H6’s BIOS limits still exceed the tolerable levels for available hardware.
The toughest test is to see how far each motherboard can stably push our Core i7 920 processor using the same voltage settings and timings. We used eight threads of Prime95 x64 to stress each configuration.
The Rampage II Gene beat the LANParty Jr X58-T3H6 in top clock speed at 1.45V core, but not by enough to consider a definitive victory. More significant is that both Micro-ATX motherboards proved more stable than the full-sized Asus P6T, invalidating myths about Micro-ATX incapacity.
A base clock of 220MHz could potentially take a Core i7 920 to 4.40 GHz, but only with a very good core and advanced cooling. A lower multiplier allowed us to bypass those special conditions to find a retail processor’s Bclk limit on each motherboard, just shy of the 220 MHz mark for both the LANParty Jr X58-T3H6 and Rampage II Gene. Both motherboards beat the full-sized P6T, again putting to rest notions about Micro ATX instability.
DFI wins the memory overclocking comparison. The second-place Rampage II Gene beats the full-sized P6T on average due to its much higher six-module results, but the P6T rises to the middle when only three modules are installed.
Asus alters the standard voltage level slightly in addition to its 0.20% default CPU overclock, but the increase in power is still somewhat surprising. Our most recent experience has shown that most motherboards typically fall between the LANParty Jr X58-T3H6 and Rampage II Gene in power consumption when using these components, so DFI deserves about half the credit for the significant disparity in power consumption.
In spite of its higher power consumption, the Rampage II Gene runs slightly cooler than LANParty Jr X58-T3H6.
