A Messy Transition: Practical Problems With 32bit Addressing In Windows

Other Problems, Other Solutions

Although for this article we are focusing on Supreme Commander, there are other games and applications that are already known to encounter this exact problem. Company of Heroes developer Relic has warned that this problem can occur, especially in conjunction with using Direct3D 10 mode and STALKER developer GSC Game World has also seen this problem. Both have gone so far as to ship the latest versions of their games with the LARGEADDRESSAWARE flag.

Although not an exhaustive list, we have compiled a list of recent games and applications and if they are flagged or not. Ideally every possible game and application that can run in to the 2GB barrier will be flagged so that it can be worked around without modifying the application directly itself.

The importance of the above applications and games being flagged is not just to avoid the need to modify the executable, but also because there is another solution to the issue we haven't talked about so far. 64bit versions of Windows(i.e. XP and Vista) do not suffer from the traditional 2GB barrier, as all the kernel mode addressing is usually moved to well above the confines of the limited 32bit addressing area. As such, these versions of Windows don't need to have their space allocations adjusted for an application to gain access to more addressing space, bypassing the instability and any possible performance problems that occurs as a result of making this adjustment.

However in order to maintain compatibility with older applications, Windows still keeps the artificial 2GB barrier in place to keep from triggering any bugs that result from the extra space. So even if we use a 64bit version of Windows, the offending application must still either be flagged by the developer or modified by the user if we want to get past the 2GB barrier.

This in turn is an interesting proposition for developers who may be looking at ways to deal with the 2GB barrier, but don't want to make the jump to having to program and support 2 versions of their executables and associated compiled code. Although as a 32bit application there is still the 4GB hard limit, flagging executables lets a developer keep a single package and is perfectly safe on both stock 32bit and 64bit installations of Windows. They can effectively buy another 2 years or so before they need to actually offer 64bit executables, and can direct users to install a 64bit version of Windows if they are hitting the 2GB barrier, instead of directing them to make the much riskier user space modification.

Of course this is not all roses. As we covered in our Vista performance guide, there are still some issues with Windows Vista 64bit, and Windows XP 64bit is even worse as a result of having been orphaned quickly after its release. For prospective 64bit Vista users, they will still find that driver support is not as good as with the 32bit version of Vista, and 64bit drivers may not be as stable as the 32bit versions. There are also still lingering concerns over application compatibility and performance.

Things have gotten better since we published our February article, but we're not ready to write them off completely yet. Users getting along with 32bit versions of Windows right now will find themselves in between a rock and a hard place as more applications and games start to hit the barrier - they'll either need to make the user space modification or switch to a 64bit version of Windows when neither of these is a perfect solution. This leaves the less imperfect but also less fun option of simply turning down the settings on any affected games. Lower settings result in lower user space usage and reduced chances of crashing, but in spite of the highest stability and compatibility offered by this option we suspect few users will actually opt for it.