Overclocking:

The goal when overclocking this system was to take the stock 3.3GHz i5 2500k processor and overclock it past 4.5GHz. Using Prime95 64bit the system would be tested for stability, and temperatures were monitored with RealTempGT 3.64, the decision was made to not load the processor past 80*C. As a result of these self-imposed limits the ASUS P8Z68 Deluxe allowed for a 42% overclock from 3.3GHz (stock) to 4.7GHz stable, requiring 1.38v VCore. As is the case with most of our motherboard reviews, we do not claim to be master overclockers. We are mostly interested in a relatively quick and simple overclock - something that the average reader could easily achieve.



Max CPU Multiplier:

Like most people who overclock the Sandybridge processors, we focused only on the CPU multiplier while leaving the BCLK at 100. Stability problems quickly show up when BCLK is increased because it affects all components plugged into the board - SATA controllers, PCIe 2.0 slots, etc. As a result, BCLK was not adjusted during the overclocking process.

Max Memory Speeds:

The GSkill memory used for this review had stock timings of 8-8-8-24-2T at 1.5V. Memory was tested for stability using MemTest86. Efforts to increase this memory to 1866MHz were not successful, even while pushing the voltage up to 1.65V (maximum recommended by Intel) or by relaxing the timings to 9-9-9-28. The system would reboot every time we tried overclocking the memory. This resulted in failed BIOS posts and required using the "MemOK" button to be pressed to reset the memory to default settings. Therefore, the memory was not overclocked as part of this review.

Maximum Overclock:

BCLK = 100
CPU Ratio = 47 (all cores)
Intel Power Settings = ON, SpeedStep = ON (for greatest power savings & performance)
CPU voltage = 0.995v at idle, 1.38v at load
CPU speed = 4.7GHz
Memory speed = 1600MHz (8-8-8-24-2T) @ 1.5v
CPU temperature (idle/load)*C = 31 / 81

Obviously for a $15 CPU cooler these overclocking results are pretty good. A 42% overclock and as you will see on the next page results in quite substantial performance gains.

Testing:

The ASUS P8Z68 Deluxe (Rev 1.0) motherboard was tested and stressed with a variety of benchmark applications.

The following is a summary of the conducted benchmarks:

» Performance Test 7.0
   - Overall PassMark Rating
   - CPU Mark Rating
   - Memory Mark
   - Disk Mark

» Windows 7 Experience
   - Processor
   - Gaming Graphics

» AIDA64
   - Memory Read
   - Memory Write
   - Memory Copy

» Heaven v2.5
   - FPS
   - Score

» CrystalDiskMark 2.2
   - Sequential Read
   - Sequential Write
   - 512K Read
   - 512K Write

» Power Utilization
   - Idle
   - Load

For the sake of comparison we will put the ASUS P8Z68 Deluxe (V1.0) up against a "reference" MSI brand board - model # P67-G43 (B3). We will compare stock performance of the processor, memory, hard drive, and 3D graphics for the two motherboards. In addition, we have added a section to each graph to reflect performance increases for the 4.7GHz overclock achieved at the time of this review.