“…be forewarned that it will take some serious high-end hardware to run Flight Simulator X at high frame rates.” - Gamespot

“For those with a middle of the road PC setup I do not recommend purchasing Flight Simulator X. The graphics will disappoint you and the frame rate will lead to insanity.” - IGN

“You need a very high performance computer to get just a normal setting out of this game. I'm going back to Flight Simulator 2004 just because I can get better scenery and performance than this one.” - Amazon customer

“You better have a monster, high-powered PC, because this game will bring it to its knees. I have what I thought was a high-powered PC... but WOW, the game is slow and the frame rates are horrendous at times.” - Amazon customer

“Realistic hardware requirements sprint right on past 'Extreme' and goes on into the outer fringes of 'Outrageous'”. - Amazon customer

Realistic hardware requirements sprint right on past 'Extreme' and goes on into the outer fringes of 'Outrageous' - Amazon customer

These are some quotes from reviews and customers concerned about the performance issues that plague FSX. And to be honest, as much as I love the new features in FSX, using it on my old mediocre PC system I didn't see the point of switching from FS9 to FSX. Yes, even Microsoft has taken note and the Aces team is currently working on a performance patch, something which is not exactly cheap and underlines that there is a performance problem with FSX. But just what is it that went wrong in Microsoft's newest release?

The amazing thing is that it is possible to get much better graphics in FS9 with much better frame rates at the same time on medium powered systems. Something in the graphics pipeline is obviously taking a severe hit. Paul Lange from the Aces team gives us a very reasonable explanation.

“In order to move FSX nearer to the cutting edge of game graphics we felt we had to move to shader 2.0 support at least (wanted to do more). This decision is a significant factor in frame rates being lower for FSX than what you would have thought we would have based on FS2004 technology. Many aspects of the rendered image on your screen are running through a shader even though it may not seem like it. If we had built FSX without this shader support, we would have higher frame rates but we would be much farther behind the times for the general gaming industry.”

If we had built FSX without shader 2.0 support, we would have higher frame rates but we would be much farther behind the times for the general gaming industry - Paul Lange, Aces Studio

Paul suggests that the new shader model is causing significant frame rate hits. But what is all this shader business? Well, shaders allow lot's of fancy rendering effects such as reflective surfaces or the so called bump mapping. Shaders basically allow live calculations on textures. For example, depending of the angle of the sun a texture could be shiny or not. FS9 was already using shaders, but their use was fairly limited. With DX9, Microsoft introduced the shader 2.0 model, which allows for much more sophisticated effects, such as the shiny surfaces on wet runways or the new reflective water textures. Each surface in FSX is a complex mix of different textures which makes surfaces look great, but at the same time uses more computer power. This is why you get less frame rates with FSX compared to FS9 even when an identical scene is rendered.

Being an avid simmer, this isn't the first time I have come across this exact problem. When I bought the racing sim GT Legends last year, the situation was very similar - great graphics and poor performance. GT Legends is using the isiMotor2 engine, which was build by ISI for their racing sim rFactor. isiMotor2 was a milestone for ISI as they moved to DX9 shaders to produce a visually stunning racing sim, allowing things like reflective road surfaces. Compared to rFactor, GT Legends pushes the graphics boundaries even more and what is rendered on the screen is just amazing. The stunning graphics have a severe performance cost, however. Nevertheless, there is a major difference between FSX and GT Legends. ISI was well aware of the performance hit you get when moving your graphics engine to DX9. In their wisdom, they ship rFactor with a small utility that let's you configure your graphics before running the sim. Using this utility, you can select which shader model you want to use: DX7, DX8, or DX9. As it turns out, you can run GT Legends quite nicely if you choose to run it with DX7. Yes, you do sacrifice some fancy graphic effects, but the sim becomes a very enjoyable experience even on lower end systems.

It seems the performance dilemma is possibly caused by one single system design decision - to move to the DX9 shader model without allowing users to run the sim with a less performance hungry shader model.

I believe, Microsoft could have learned a lesson from ISI and implemented a similar system. This would have allowed users of midrange systems to select DX7 or DX8 and get the same visual quality as FS9 with the same frame rates. Yes, they would have to sacrifice bump mapping and the shiny wet runways, but at least they could have enjoyed all the other new features, like the mission system, the fantastic gliders, the living environment and possibly even visual enhancements such as the higher resolution ground textures. It seems the performance dilemma is possibly caused by one single system design decision - to move to the DX9 shader model without allowing users to run the sim with a less performance hungry shader model.

In the end, did Microsoft fall into the trap of overestimating what computer system the average user owns? Were they too confident about what DX9 can deliver on an average desktop? It appears so.

Christian Stock

About the author:

Christian Stock has been a keen flight simmer since FS2000. He is one of the leading scenery designers in the MSFS scene and has published several scenery creation manuals, ranging from scenery coding over terrain scenery to weather theme creation. He has also written occasional opinion piece and several flying tours. He and his young family currenty reside in Melbourne.