Currently we are running WinXP32bit and 3dsMax2010.  I want to upgrade to 64bit to take advantage of the added RAM.  I having been reading about lot of issues running 3dsMax2010 on Win7, which was my first choice. 

I figure I can either upgrade to Max2011, and use Win7_64bit.  Or…
I can upgrade to WinXP64 and use Max2010.  (Not really interested in Vista from the poor reviews)

Which 64bit OS runs Max2010 the best?
Which 64bit OS runs Max2011 the best?

HP xw8600
Dual Xeon E5440 2.83GHZ
4GB RAM
NVIDIA Quadro FX 4600 768MB
WinXP 32bit SP3

I am leaning towards Max2011 64bit and Win7 64bit, even though the forum is flooded with issues and complaints with that configuration.  Mostly, people seem to be having a lot of difficulty with the viewport performance.  I have yet to get much of a response from Autodesk, or any retailers about this issue.

HP xw8600
Dual Xeon E5440 2.83GHZ
4GB RAM
NVIDIA Quadro FX 4600 768MB
WinXP 32bit SP3

I use Win7 x64 and max 2011 x64 - everything is OK, Yes, it crashes somtimes… but it is ussual for all MAXes. Only problem is circle when use tablet, it appeares sometimes - can’t turn it off.

i use windows 7 x64 and max 2011 x64 and love it.

@Terskov Alexander
there are 3 things i do to get my wacom working perfectly in windows 7
Issue #1: Every pen click produces a gray splash/ripple animation around the cursor
1. Open Local Group Policy Click the Start button , in the Run field type: gpedit.msc and hit enter
2. Navigate to User Configuration - Administrative Templates - Windows Components - Tablet PC - Cursors
3. Right click on Turn off pen feedback
4. Select Enabled, Click Apply

Issue #2: Photoshop will lag when you try to use your pen pressure to drive a feature such as fade. Pressing down too long will launch the right click menu.
1. Click the Start button , click Control Panel, then click Hardware and Sound
2. click Pen and Touch
3. Highlight Press and hold, then click settings….
4. Uncheck the Enable press and hold right-clicking

Issue #3: A handwriting dialog appears on the edge of the screen when using the tablet
1. Click the Start button , click Control Panel,
2. click Programs
3. click Turn Windows features on or off.
4. Uncheck Tablet PC Components
5. Restart

3Ds Max 2012+Sp2 +SAP, Vray 2.2, Photoshop CS5.1
OS - Windows 7 Pro x64 Sp1
sys1: i7 2600k (OC to 4.2GHz), 16GB 1600mhz DDR3 Ram, MSI GTX 580 (3GB) (295.51), OCZ vertex 2 120GB SSD, Wacom Intuos 3
sys2: i7 2600k (OC to 4.2GHz), 16GB 1600mhz DDR3 Ram, MSI GTX 560 (1GB) (295.51), wacom bamboo

Has anyone had any problems using Xeon e5440 processors in Win7 64bit?  I am being told that I might have some issues because those processors are not designed to deal with memory the way newer processors, like those found in the HPz800 are.

HP xw8600
Dual Xeon E5440 2.83GHZ
4GB RAM
NVIDIA Quadro FX 4600 768MB
WinXP 32bit SP3

you were misinformed, there won’t be a problem

3Ds Max 2012+Sp2 +SAP, Vray 2.2, Photoshop CS5.1
OS - Windows 7 Pro x64 Sp1
sys1: i7 2600k (OC to 4.2GHz), 16GB 1600mhz DDR3 Ram, MSI GTX 580 (3GB) (295.51), OCZ vertex 2 120GB SSD, Wacom Intuos 3
sys2: i7 2600k (OC to 4.2GHz), 16GB 1600mhz DDR3 Ram, MSI GTX 560 (1GB) (295.51), wacom bamboo