Ocaholic did further testing to discover the root cause of Windows 8's RTC issues, you can read it over here. One of the things that the site discovered is that on AMD-based Windows 8 PCs, there's a "useplatformclock" parameter in the Windows 8 Boot Configuration Data (BCD) that is set to "Yes" whereas on Intel installs this parameter is missing. By adding this parameter and setting it to yes on Intel platforms it effectively fixes the Windows 8 RTC bug. Additionally, the site also discovered that the same parameter can be abused to mess up the RTC on AMD platforms, which means AMD-based Windows 8 benchmark results can't be trusted either until this bug in Windows 8 is fixed.
As soon as the Windows 8 RTC issue appeared, we started our own investigation and found out, that only Intel setups were affected. But still there were quite a few questions unanswered like for example: which timer is Windows 8 actually using, are there really no issues on AMD and why is the issue fixed, when you move to an Intel when you installed Windows 8 using an AMD platform? Credit also goes to Franck D. from CPUID, who was kind enough to provide us with a tool to read out different timers and their frequency.