What Hardware to Buy

X-Plane 9 requires a computer with at least the following specifications:
 * A 2GHz processor
 * 1.0GB RAM (physical memory)
 * 32MB VRAM (video memory on your video card)
 * 10GB of hard drive space

The simulator will run on Mac OS X version 10.4 or later, Windows XP or Vista (both 32- and 64-bit), and Linux. Note, however, that when using Windows Vista, it is recommended that at least 2 GB of RAM be used.

Of course, a computer with 4 GB of RAM, a quad-core processor, and 2 GB of VRAM can be used and X-Plane will take full advantage of it. CPUs with multiple cores are useful because X-Plane will use that second core to load scenery while flying. This eliminates the tenth of a second stutter usually associated with transitioning from one scenery file to another (which is still experienced when using a single-core processor).

Now, a few notes on hardware:

Hyperthreaded CPUs are little more than marketing “hype.” The old Pentium 4 Hyperthreading chips are really just one CPU pretending to be two. This does not provide anything near the performance boost of using two discreet CPUs or a dual-core CPU.

Regarding video RAM (VRAM, present on the video card), some cheaper video cards advertise having more memory than they actually do. NVIDIA calls this TurboCache, while ATI calls it HyperMemory. The video card itself may have only 64 MB of memory, while advertising that it “supports” 256 MB of RAM. It does this by “stealing” the other 192 MB from the system RAM. While this might give some performance increase, it is nowhere near as desirable as having a true 256 MB of RAM on the video card. This is especially important for systems that barely meet the system requirements for RAM as it is—for instance, if the system has 1 GB of RAM, but 192 MB of that is being reserved for the video card, X-Plane only has 832 MB of system RAM to work with.

Also, while Intel makes a fine CPU, their integrated video cards are, at the moment, awful for X-Plane. They are the only cards at the moment that the software doesn’t support outright, though their much-hyped “Larrabee” chip could change this.

Now, about VRAM speed—the "memory bus width" of a graphics card (such as 64-, 128-, or 256-bit) indicates how many bits of data it reads at once each time it reads data. Basically, the wider this is, the faster the graphics card can draw things. Today's most powerful high end cards have a 512-bit bus; most mid-range cards are 256-bit, and the cheapest cards are 128-bit.