Overclock update with Asrock Z87 Extreme 4 Bios 2.70

Overclocking adventure!


Asrock released a couple of new bios since 2.30 but due to busy schedule, I have postponed it until now. I decided to give Windows mode update a try but the entire process isn't smooth sailing at all. For the first time in over 10 years of hardware enthusiast, I encountered boot loop after a bios update. Fortunately, a simple CMOS clear is required to get it back up and running. Furthermore, I cannot pinpoint the blame on Windows update mode as other mode of update may have this problem.

In addition to bios update trouble, I noticed the new bios do not have the ability to run any base clock other than 100. Even a small change like 100.1 will result in slow boot up to bios or total failure with error code D6.

At the mean time over the months, I researched into Haswell's overclocking behavior from multiple sources. Below is a quick summary of what I've learned.

• CPU Uncore can be left at stock with minimal performance impact (34x for 4670K and 35x for 4770K)
• Uncore voltage should be 1.15V even when its running at stock frequency
• CPU VIN should be at least +0.5V of CPU VCORE
• Asrock Bios sucks when left at its default settings.  (auto settings will adjust voltage to high and cause temperature issue)
• CPU should not be above 95C during stress test

Armed with this knowledge I attempt to break the 4Ghz barrier in my past overclock attempt. After all, most Haswell are supposed to hit 4.4Ghz with minimal effort. So below are the following settings I used:

• 44X Core
• 34X Uncore
• 1.25V VCORE
• 1.15V VUNCORE
• 1.8V VIN
• Level 1 LLC

All attempts to lower voltage while maintaining stability proved futile, pointing to a rather poor quality chip that I owned. Furthermore, 45X Core would lead to instant blue screen at boot up, signaling a need of much higher voltage bump.
The voltage bump from my 40X is also insane, a 0.125V increase. This leads to 15 C increase in temperature, staying near 95C load using AVX linpack. I will stick with this overclock for now since normal usage did not stress the temperature above 60C and I didn't buy a close loop water cooling to run at low frequencies. However, if you care about performance per watt, 4.4ghz probably isn't for you when you possess sub par silicon like mine.