Windows Vista Performance Guide

Vista x64

One of the major changes on paper for Vista is that x64 now becomes an equal platform with the x86 version, as using the Vista compatibility logo on any hardware or software requires that the item in question works under both the x86 and x64 versions, but the reality of the situation is not as rosy. Along with the other limitations of the OEM versions we listed above, only the retail versions of Vista are shipping with x64 and x86 together; the OEM versions are only sold in an either/or fashion: you can either get the x64 or x86 version, but not both at once. It's possible that this will be trivially easy to work around, however it's something that should be kept in mind if you're purchasing an OEM copy.

As for how well the x64 versions of Vista work, in our first article we called x64 the black sheep of the Vista family, as it was clearly behind the x86 version in terms of compatibility and performance. While we had hoped that Microsoft would remove the gap between the two versions, in our testing this has not completely been the case. Vista x64 is still the product of all the compatibility problems of Vista with all the compatibility problems of a still-young 64-bit platform.

This is not to say that Vista x64 hasn't improved; if anything it has improved more between Beta 2 and now than the x86 version did, if only by virtue of having more ground to cover. The performance gap we initially saw between the x86 and x64 versions has dissolved away in most cases, so x64 no longer means taking an immediate performance hit in benchmarks. However we can't shake the feeling of Vista x64 still being slower, even if the benchmarks don't show it. We've had multiple editors use multiple machines, and general performance in particular just feels slower. At this point we still are unsure why this is, but it's a very real condition that hurts Vista x64.

On the positive side, driver support for the x64 version seems to be about as good as the x86 version (although more testing will be required to completely confirm this). The biggest problem as far as support goes is the applications. Not every application is happy working under the Windows-on-Windows (WoW) compatibility environment for 32-bit applications, and this is on top of the applications that don't work with Vista period. There are very few major applications available with x64 binaries, so without 64-bit applications everything still remains in the 32-bit world for now. Furthermore, as we will also see in our graphics tests, having a 64-bit application doesn't necessarily mean we won't see any performance issues.

At this point Vista x64 is certainly usable if you need it, but we wouldn't recommend it unless you have a specific reason to go that route (i.e. applications that can use more memory). Except in a few cases where 64-bit code is clearly faster, the primary purpose for Vista x64's existence is to resolve the problems of 32-bit addressing space, and we're just not at the point yet where even most enthusiasts are pushing that limit. Once applications begin to push the 2GB addressing space limitation of Win32 (something we expect to hit very soon with games) or total systems need more than 4GB of RAM, then Vista x64 in its current incarnation would be a good choice. In the meantime, Vista x64 shouldn't be used until it's needed or SP1 comes out - whichever comes first. The black sheep isn't ready to rejoin the flock quite yet.