- Sep 19, 2007
64bit is more powerfull in EVERY way. No reason to go for 32bit (running 32bit apps in virtualisation causes overhead, so you wont get the performance benefits in a 32bit program, a slightly slower performance).
I think you've missed the point about Virtualisation here.
The main issue (in this case) is to be able to run legacy hardware and applications for which there aren't any 64 bit drivers etc for all sorts of reasons including some basic one's like \"Manufacturer no longer exists but equipment still perfectly good and serviceable). A lot of this kit is usally pretty high end gear of a profressional standard - far removed from consumer grade hardware and not normally seen in a typical home or office. It can also cost 100's to 100,000's of dollars too.
In these cases the \"efficiency\" of the VM isn't an issue -- and in any case with todays hardware the overhead of running these types of Virtual machines is relatively small. All you basically need is OODLES of RAM and enough disks to accomodate the Virtual machine with its OS, data and applications. Even the OODLES of RAM isn't significant these days as most desktops will have AT least 4GB RAM and may be as much as 16GB. A typical legacy application can run EASILY in most cases on a 512MB Virtual XP machine. --The way VM's work is too complex for this post but there ISN'T a relation of 1:1 between resources of HOST OS and Virtual Machine. The only thing the VM consumes a lot of is RAM - your 512MB RAM VM will use all of the 512mb. However virtual paging and Virtual I/O is done in a very different manner than that of the \"Real OS\".
In some cases you can actually get a VM to run at around 90 or even 95% of Native speed -- and considering XP systems are usually pretty OK that's good enough.
With the XP compatability feature in W7 there really isn't any reason after this release to continue supporting NEW 32 Bit OS'es any more. Once the Atom processor (used in a lot of Netbooks) is 64 bit enabled then W7 x-64 could even run on these as well.
Looks like MS have made sense in that this is a better route than to offer an \"XP Downgrade\" from W7.
(Note the XP compatability feature is a FREE add on to W7 which will become available later. I think you'll need a separate licensed copy of XP SP3 to use it however)