Those who have been following the problems when using Vista for gaming are certainly aware of the memory problems being faced. Anyone using video cards with large memory caches (512 and up) have certainly hit the ceiling where games can do strange things without warning – and up until lately, without explanation.
The testers at AnandTech have been doing a series on this problem, and have noted when and where the problems occur, but until part 3 of the series have only been able to postulate what the root cause could be.
Now Microsoft is helping out, with the release of the above mentioned hotfix, which is not, as yet, available widely. While awaiting the widespread release, the reasons for the fix, and the cause of the memory grab by the operating system, not duplicated in Windows XP, have been given.
The Windows Display Driver Model, rewritten for Vista, is the culprit here. The explanation for the problem has to do with Microsoft making the memory management for the system video a part of the OS, and relieving applications from doing the management. The problem occurs when older games (at this point, nearly all of them)are used. The games are trying to manage memory, and setting aside a pool, while Vista is doing the same. The memory pool is doubled, and there is where the system runs out, and experiences strange behavior.
KB940105 will take care of this – but Microsoft also says that the fix is still ‘really hot’, as it is still in the process of change. It will be available for wide release soon, and testing shows it does alleviate some of the memory usage. Perhaps the further tweaking will bring memory usage in line with the same game’s memory footprint when used with XP.
[tags] hotfix, Vista, Microsoft, video memory pool, video memory management, WDDM, KB940105 [/tags]