Hello folks. I have a weard problem with my setup : before : Intel dual core E6600 running stable overclocked at 3+ GHMotherboard : ASUS Commando BIOS 16044 GB paired Corsair (4x 1GB modules, paired 2 by 2).videocard nvidia 8800GTS 640MBNever had a problem, except for some crappy nvidia drivers (I do like testing beta) .after : 1st upgraded BIOS motherboard to 1801 to support the new processor2nd : I set all BIOS changes back to standard3rd : installed Quad core processor Q9550Problem : boot fails before getting to first screen (the one with DEL to go to the bios). On the small panel at the back of the motherboard, I read something about memorytest.Solution : removal off any of the modules. I can boot into windows Vista 64 bit without problems with 3 GB installed.2nd solution : I put the old E6600 back in. Again I can boot into Vista with all 4 GB installed.The problem is with any of the modules, as long as I have 3 GB in, I can boot the Q9550.Question : anyone else has seen a similar problem ? I would like to go back to 4 GB, because that gives the OS a little headroom. I know FSX has no benefit for more then 2 GB, but my hard drive is definitely trashing louder then before.And I use my PC for other things then flight simming too.I suspect the BIOS, but I would like some feedback.BTW, this upgrade did it, I took off from JFK NY, with traffic at 100% and autogen at 100%, with a steady 14 FPS. Next : overclocking.Jan

No answers from the HW guru's, but I want to give feedback for those that would have the same issue. I stumbled upon this post in the ASUS forums : http://vip.asus.com/forum/view.aspx?id=200...SLanguage=en-usThe common demoninator : 1> ASUS Commando gamers Motherboard 2> latest BIOS 1801 3> CPU that needs above BIOS (works for me with my old E6600 and new 1801 bios)4> More then 2 GB of RAM (I got it working with 3 GB, but got one BSOD already while playing halflife)Problem : freeze during check of memory.Solution : use only 2GB :(Now I can only wait for ASUS to come up with a working BIOS. In the meantime, I bookmarked the thread.Hopefully this can help someone else who is in the same boat (aeroplane?) as I am.regards, Jan

Thanks Jan for your findings.Many folks take help but once their problem is solved they rarely come and post their feedback.Manny