Hmm sounds to me that the OC is not stable. Have you managed to pass a 12 hour Prime 95 test? It seems to me everyone around the OCN forum hold this to be the stability confirmation boundary.
If you haven't done so I'd start with that.
You say that if the system is at stock settings you dont have this problem at all. I've just had a quick skim through the thread and haven't seen you mention your settings at all, so I don't know how much of an OC you're running with. But when I've ran into windows hanging it have been because of two problems:
1) GPU drivers / card faulty, when windows tries to load the GPU drivers it would hang and once I changed my card and reinstalled the drivers it has worked flawlessly ever since.
2) Unstable OC that wont allow the user to boot into windows.
Any information on the OC itself will be very helpful as it will allow others to get an insight into your system and your setup.
In your case, I would probably return everything to stock and see how I get on with the booting and double posting. If I see that when on stock everything is ok, I'd start OC'ing. Start with something tame like 4.3Ghz, see if you can post and login without any problems, and slowly work up from there.
As mentioned elsewhere in the thread the PLL Overvoltage helps ensure stable overclocks at higher speeds, but it is recommended for it to be disabled. When I set up the OC as it was my first time OC'ing I ran with the PLL Overvoltage enabled. I was somewhat hesitant to turn it off, but the double posting because a massive issue for me.
The Asus bios has a number of other functions as well, and I found the following link
useful when setting up my OC.
Maybe if you have a read through that, and work from stock back up to your desired OC you'll get your system stable.
My voltage is at about 1.376..should this be raised, I have seen alot of folks who have overclocked to 4800 with 1.4 voltage.. could this be a contributing factor?
In regards to the voltages, each chip is very different. One might work perfectly with 1.376 another may need 1.4. From all my readings on the subject, you can increase voltages, but you are going to see a heat increase. If your cooler can keep the temperatures at a good level and you are not exceeding the recommended voltages then increase the voltage as the chip may simply need more volts.
I am no expert on this part at all. My rule of thumb on the matter is that if the temp is ok, and the system is stable then I must have my voltages near enough correct. The only way you can really find your correct voltage is to do a bit of trial and error, change voltages for a certain speed, run a few stress tests and see how the computer reacts.
But I think the first thing you need to establish is a stable OC and then from there you can begin to tinker in relation to higher multipliers, voltages, and other settings.
Hope this helps you somewhat Edited by 5nak3 - 12/8/11 at 1:48pm