I run Windows 7 Ultimate 64bit and am running on a Dual Core CPU. I always get random crashes and common dual core bug unless I set the affinity manually for EQ after I first start the program. Once the affinity is set though, it all runs perfectly.
One thing I am going to look into tonight is getting EQ to start from the shortcut to automatically use only one of the cores. This should stop me from having to set it manually each time.
This is a little thing I wrote up on my wiki that I am going to test out tonight and see if it works:
Setting EQ to Start using only 1 CPU:
Windows Vista/7 has an option that lets you start an application and set the CPU affinity,
which assigns the application to run on a specific CPU in a multi-core system.
To start an application you have to pass the affinity flag to the start utility in the command prompt.
For instance, if you wanted to start notepad assigned to CPU, you could use the following command:
c:\windows\system32\cmd.exe /C start /affinity 1 "c:\Program Files\Sony\Everquest\eqgame.exe" patchme
You will need to adjust the path name of the file that is in quotes so it knows where to find your eqgame.exe file.
You should be able to add this line to your shortcut, but I will need to test it and update here if it works or not.