A little trickier to capture with benchmarks is the performance benefit of additional memory actually within resource-hungry games themselves.
Architects inspired by the wild
Developers tend to architect their games to suit the real PCs being used in the wild. Presently, 4GB systems remain relatively scarce. But although benchmark scores tend not to reflect any clear advantage of expanded memory availability, the subjective experience is a slightly different matter.
A good example is something like Oblivion. That title constantly loads data in the background as you explore the game universe rather than periodically calling a total halt to proceedings and loading the next section of the level, as with the likes of Half-Life 2. More memory makes for less disk swapping and a generally smoother experience.
Performance also tends to be a little smoother immediately after level loading in a really data-intensive title like Crysis. The data caching that takes place the first time you fire up a given level is that little bit less of an issue when you have more memory available, as our benchmark results reflect.
Poor memory causes instability
The situation can be even more critical with the most demanding RTS titles. When the poo is really interfacing with the rotational cooling device in the likes of Supreme Commander, limited system memory can actually cause instability.
In fact, Supreme Commander developer GasPowered has gone as far as to recommend the use of an advanced user patch from Microsoft that removes the 2GB address barrier that usually applies to any single application regardless of the amount of system memory available. Without the patch, some users find it is simply impossible to complete some of the larger, more advanced maps.
In the end, therefore, we suspect you will have to grudgingly admit that the benefits of having more than 2GB of RAM are probably broader than you imagined. And with memory so ludicrously cheap at the moment, this is an upgrade you really can't afford to ignore. Go on, do yourself a favour.