The question is obviously vague, because it varies from game to game and between different settings in the same game. But to get a rough idea of how much RAM – and much more importantly video RAM – modern games require, we are going to take a measure of a few popular games.We can establish right away that, out of these two values, your main system memory (RAM) is clearly the least important factor of the two. As opposed to the memory modules soldered onto your graphics card, it is also user upgradeable. Besides, any gaming laptop on the market today will ship with enough RAM to satisfy even the most demanding games.
The graphics memory, on the other hand, is where the magic happens. Depending on texture size, resolution and post processing effects, your games will require a varying amount of space. VRAM is also impossible to upgrade, but fortunately most laptop graphics cards are also well equipped in this area–better, in fact, than most desktop cards. An important thing to keep in mind also is that less powerful GPUs require less video memory, simply because they can’t handle high resolutions and advanced effects.
But let’s move on to the actual numbers. The test system is the EON 15-S, equipped with a GeForce GTX 580M from Nvidia with 2GB of GDDR5 video RAM, which is the fastest mobile GPU at present and also happens to be identical to the “new” GeForce GTX 675M. RAM and VRAM use varies over time, so we have used the same scene or savegame to get comparable values. The game settings compared are the highest possible in 1080p Vs. a medium preset or setting at 1366×768 resolution to mimic what you might achieve with a mid-range gaming laptop, such as the new Acer Aspire M3 ‘ultrabook’.
Skyrim is a DX9 game and is not overly demanding even at the game’s Ultra preset and with high-resolution textures installed. In our outdoor test scene it maxed out at just above 1GB of VRAM, while using much less at the 1366×768 resolution and the Medium preset active.
For a turn-based strategy game Civ 5 is unusually demanding and utilizes DirectX 11 tessellation effects (when you run the DX11 version of the game). In our test, which is late in a game on a large map with lots of active units, the game actually uses almost 1.5GB of video memory. This number is however significantly reduced when the game runs in DX9 mode and medium settings.
BF 3 requires a relatively powerful GPU to run at all, and it looks pretty great regardless of the preset. The test scene is a multi-player battle on the Kharg Island map and the video RAM use hovers around 1GB regardless of resolution or level of details.
Crysis 2 is another game with two entirely different modes, using either DX9 or the newer DX11 version with tessellation and optional high-res textures. The frame rates vary accordingly, and so does the video RAM use, apparently. This is the only game that uses up the full 2GB on the GTX 580M, but it’s also barely playable with all the details maxed out and high-res textures installed. Interestingly, system RAM use drops noticeably at the higher setting. The test scene was Central Park.
The Witcher 2
The Witcher 2 is also a great-looking game, and quite demanding. However, the difference between the Medium preset and resolution and the Ultra preset (including “ubersampling”) is surprisingly small.