A bug relating to the real-time clock has been discovered in Windows 8, which causes inaccurate benchmark results on over- or under-clocked systems. When a system's CPU clock frequency is adjusted from within the operating system, the software time-keeper no longer reports the time accurately, slowing down with an underclock and speeding up with an overclock.

The team at HWBOT did some research, finding that after a 6% CPU base clock decrease, the system time after five minutes lagged behind actual time by 18 seconds. In benchmarks this translated to a 5-7% score boost, when compared to a system of equal clock speed modified only through multiplier adjustment. Conversely, a base clock increase caused a score decrease in the same benchmarks.

After discovering the issue with Windows 8, HWBOT are no longer accepting benchmark results produced on the operating system, and are invalidating all previous Windows 8 results. There is the potential for overclockers to use the real-time clock bug to their advantage, and HWBOT want to ensure there is no potential for cheating. Windows 7 and previous operating systems are unaffected by the issue.

The real-time clock (RTC) is a hardware feature of many computer systems that keeps accurate track of the current time. In some low-cost and embedded systems, the RTC circuit is removed to save costs, and with Windows 8, Microsoft made several changes to preserve time-keeping compatibility with these machines. Now that it has been discovered that these changes affect benchmarks in some situations, Microsoft may have to look into patching the issue.