Never had that 4GB Vista problem. Now that I'm used to Vista 64 sp1 I never boot to Xp64 again. It takes longer to configure Vista into the settings I want it in but once that it is done things are running smoother than all XPs' before. For instance extracting larger files goes smoother, XP tends to stutter a bit at times. The only real thing I lack in Vista is proper classic explorer and full EAX support.
The 4GB Vista problem is for people that have a Vista CD that does not have SP1 on it or the hotfix that Microsoft released. All you have to do is take out a stick of RAM, install Vista, then update to SP1. If you could install Vista without getting the BSOD, there are no worries. This has nothing to do with Vista when it is running, this ONLY has to do with installing Vista. For example, I have 2x2gb sticks. When I put in my Vista install disk, it would BSOD. I took out 1 stick and it installed fine, then I updated to SP1, then put in my other stick and things are running great. Microsoft released a fix for this, it is a known issue. Despite my computer running fine with 4gb, I decided to install vista again, and when I put the CD in, I BSOD. You cannot boot to the Vista CD with 4GB of RAM (If the CD is older and does not have SP1 or the hotfix).
I recently did a fresh reinstall of Vista64 after some borked modifications!!! I had no issues installing with 4GB! No BSOD!
How old is your Vista DVD? I have an old Vista DVD and I BSOD with 4GB. Right now, despite that fact that I am in Vista x64 running 4GB of ram, if I put it my Vista DVD and booted from it, it will BSOD.
Two cases for 4GB+ RAM on Vista64: http://www.bit-tech.net/hardware/2008/07/08/is-more-memory-better/1 http://www.tomshardware.com/reviews/vista-workshop,1775.html
You figure out your problem yet Moogy? Have you tried running with 1 graphics card and only one monitor to see if the crashes continue? Also, post the exact error code you get if you could. It would help a lot.
I haven't had it happen recently, but I've specifically stayed away from dragging between "video cards". The issue seems to happen when I take graphical windows (like EVE Online) and drag from my main monitor to a sub (2nd card) monitor or vice versa. Also, using WebEx on my main and moving things around on a 2nd monitor seems to cause the problem as well. I'll try to take down the error code next time, but it's always in the video drivers. Seems the problem revolves around managing graphic systems between the two cards...