I have the M6F myself and yes it is a beautiful board, especially if water cooling. However, both are affected by the BIOS Clock Freeze bug whereby if you use certain BIOS features and sometimes for no reason at all, the BIOS clock freezes. Once that happens it's like the movie "Groundhog Day where Bill Murray relives the same day over and over. Once the freeze occurs, every time you boot the machine, you go back in time like Bill did and the machine "wakes up" at the same exact day / time every reboot.
There is a method to reset it and it involves clearing CMOS, reinstalling BIOS, and then re-inputting all your custom BIOS settings. One way in which you can get it to happen is to save or load BIOS profiles in the tools section. But users have also had it happen after a crash, and for no reason that they have been able to determine.
http://rog.asus.com/forum/showthread.php?35490-Sabertooth-Z87-Bios-Clock-Issue&p=404524&viewfull=1#post404524
"I have 3 boards with this issue in my shop and EVERY client system I built has this problem. I have tried EVERY fix in this thread, nothing works for more then a few days. Flashed BIOS, reset to factory, replaced batteries. NOTHING. "
It was first reported as affecting the entire Z87 lineup is afflicted, there are numerous other posts on the RoG / VIP forums detailing this. Here's **some** of them
http://rog.asus.com/forum/showthread.php?45079-BIOS-Time-Clock-not-Keeping-Correct-Time-or-Date
http://rog.asus.com/forum/showthread.php?35490-Sabertooth-Z87-Bios-Clock-Issue
http://rog.asus.com/forum/showthread.php?49989-VII-HERO-Clock-never-changes-hour
http://rog.asus.com/forum/showthread.php?49904-VII-Hero-Real-Time-Clock-Issues
http://rog.asus.com/forum/showthread.php?35490-Sabertooth-Z87-Bios-Clock-Issue
http://rog.asus.com/forum/showthread.php?33895-Hero-Time-Clock-Problem
http://rog.asus.com/forum/showthread.php?46242-Hero-boot-shutdown-time-clock-error
http://rog.asus.com/forum/showthread.php?47956-General-issues-with-the-Maximus-Vi-Formula
A thread entitled "The Fix" for the Asus BIOS Clock Freeze Problem was started by an Asus staffer. It starts off stating:
"Is your motherboard suffering from the malady of a frozen time clock in UEFI?"
http://rog.asus.com/forum/showthread.php?36676-Frozen-Time-Clock-in-UEFI-The-Fix
This is the procedure I mentioned above but to give ya a heads up before reading the thread, it's only temporary.
1st post here shows it affecting Z97 boards as well ..... you'll find similar postings in newegg user reviews and in other forums like OCN
http://rog.asus.com/forum/showthread.php?36676-Frozen-Time-Clock-in-UEFI-The-Fix/page33
In one of the threads, a BIOS fix was announced on June 11, for 12 different
non ROG boards. It was stated that the BIOS release notes would state "RTC Issue Cured" and that a new BIOS for RoG boards will follow. No such BIOS has ever been issued.
http://rog.asus.com/forum/showthread.php?35490-Sabertooth-Z87-Bios-Clock-Issue&p=408653&viewfull=1#post408653
I would also advise you that, according to Asus, the use of LAN / WiFi is an either / or thing. While WiFi is nice on the workbench, I prefer a LAN connection and when setting them up had issues so called TS. I was advised that this was not possible. I questioned this as my laptop manages just fine and their response was that "laptops are designed to do this" but they don't support both components being enabled at the same time.