Fans of Flight Simulator are frequently left scratching their heads after installing FSX on their existing machines, because it is an extremely demanding program. However, tackling it has proven extremely difficult, partly because typical solutions like an ultra-powerful graphics card don’t work for it, and in some instances such as with SLI, actually slow it down!
FSX is what is known as CPU-bound. What that means is that it is usually limited by the CPU, not the graphics card, RAM or other components. This is in stark contrast to most games, because they rely primarily on graphics cards. Even the most demanding games, such as Crysis will vary widely with different graphics cards, but will not be affected much by changes in CPU. Even though FSX is CPU-bound, you still need to give it enough RAM and graphics performance so that those factors don’t limit it. Here’s what you need.
RAM – FSX is a 32-bit application, so it can’t use more than 4GB of RAM. If you’re building a new system based around the Core i7 architecture, getting 6GB of RAM is more than enough, and fairly cheap as well. RAM speed does not really affect FSX performance.
Hard Disk – Generally, FSX performance isn’t affected too much by the hard drive, except when loading textures. While some people like to use a hard drive just for FSX, it’s not necessary. If you choose to go that route though, I’d strongly recommend an SSD for its near-zero access time.
Graphics Card – FSX does not respond well to ATI cards, plain and simple. If FSX is important to you, then do not get an ATI card, period. All non-integrated Nvidia-based graphics cards perform as well as can be expected, but in some cases, having more video memory helps. Go with something above 512MB if you can. I recommend the GTX 260, 280, 275 or 285. Do NOT get a dual-GPU card or use SLI, because this will actually limit performance big time.
CPU – The biggie. Let’s clear something up right away. FSX likes Intel CPUs, not AMD. There’s no debate on this. Then there’s the question of faster dual cores vs. slower quad-cores. I have extensively tested a number of systems, so I can tell you this – FSX likes the fastest clock speed possible, above all else. If you are comparing a 3.33 GHz dual-core to a 2.66 GHz quad-core, the dual will be far better for FSX. While FSX is multi core aware, it relegates secondary and tertiary tasks to the other cores and they don’t affect the framerate all that much. You could even say the framerate in FSX scales directly with CPU clock speed. This is why many people look into overclocking. I would not be interested in running FSX with a CPU under 4 GHz. If you can get a quad-core that can overclock and stably run 4 GHz or more, go for it, but if that’s hard, then definitely go for a super-fast dual-core, like the E8400, E8500 or E8600 Core 2 Duo models and overclock it to 4.3 GHz or so. I found that the Core i7 920 was the best value, because not only is it faster clock-for-clock, but it also overclocks very well – I run mine at 4.2 GHz all day.
So why is FSX like this? Well, FSX was designed back at that point just before dual-core CPUs came out and clock speeds were on the rise. Remember the 3.8 GHz Netburst P4? Basically, its engine is old and nothing much can be done at this point. Aside from the above hardware recommendations, I would also say you run FSX on 64-bit Windows 7 or Vista, have all your drivers updated, and look into getting the REX (Real Environment Xtreme) addon, because not only does it look great, it actually helps your framerate. Happy simming!