Experience with Windows on machines with 4GB RAM or more:
- XP 32
Downgrade is OK, but not whole RAM can be used.
Starting to get driver problems on very new machines.
Still suits most cases. - XP 64
Forget it. No good drivers available. - Vista 64
It's Vista (slow file copy operations and other such problems.)
Users just don't like it. - 7 64
Only available as RC1...
I wonder which Windows you are installing on such machines.
For now it seems we'll have to hope and pray for 7.
Edit:
- This was not clear in the original description: It's about machines for users (desktops and laptops). Not servers.
- I was referring to XP SP3 and Vista SP1 above. From my experience and those of the users Vista x64 SP1 still has slow file operations, even though I agree that it has much improved over the disaster in Vista without service pack.