Monday, February 18th, 2008

DirectX 10 in Microsoft Flight Simulator (FSX) – Amazing graphics or a load of hot air?




Recently there has been a lot of controversy surrounding FSX and its graphics (although these days it seems like any new Microsoft product leaves at least several user groups up in arms). Browse any FSX related forum and you’ll likely see third-party developers expressing their frustrations with the FSX team over a variety of compatibly issues including, among many others, the introduction of DirectX 10 (DX10) to the Flight Simulator package via the recently released Acceleration Pack or SP2.

Just as a reminder it’s worth mentioning that, at the moment, DX10 is only available in Vista. To use DX10, you also need a DX10 compatible graphics card.

What we once thought we were getting…
The gaming community’s response to the introduction of DX10 to FSX has been, to put it lightly, a bit rough. It all started prior to the release of DX10 for FSX with two images that quickly spread around the Internet and, not surprising, had the FS community drooling with anticipation. It was said that these two images (seen below) demonstrated what we could expect from DX10 in FSX.

FSX DX9 Image

FSX DX10 Image

Much attention was focused on the difference in water effects, with everyone commenting that the water in the DX10 images looked photo-realistic. However, it turned out that in reality you’ll never see anything like the graphics shown in this FSX DX10 image. Why? Because it wasn’t real. As it turns out, this was not in fact an actual screenshot of the DX10 that was to be released for FSX, but an ‘artists depiction’ of what it might look like. Ooops. And hence started a series of additional DX10 disappointments for FSX users.

So are the graphics really fantastic in DX10?
In short, no not really. In the end, all we got was, as labeled in the software, a ‘DirectX 10 Preview’ (whatever that means). It’s not all bad and there are some benefits (see below), but the overall quality of the graphics is essentially unnoticeable between DirectX 9 (DX9) and DX10 based FSX. Case in point, take a look at the images below comparing identical scenes with identical settings (all maxed out except the autogen scenery) between FSX in DX9 and DX10.

The smaller versions of the images below are provided for context only so please click the associated links to download the original bitmap files as captured by FRAPS. These original files are quite large, but I didn’t want to use any sort of image compression (e.g. converting them to a jpg) in order to precisely preserve all of the data in the original capture.

DirectX 9 (Click here for original image, 6.6 MB)
DX9 Image

DirectX 10 (Click here for original image, 6.6 MB)
DX10 Image

The first pair of images shows a generic scene (above Harrisburg International Airport) chosen because it features a nice balance of clouds, water, land, buildings, mountains, trees and other scenery features. After closely examining each image you’ll see that they are almost totally identical. Without spending a bit directly comparing the two, you could be easily convinced that in fact they are exactly the same.

A close inspection reveals that there are some very slight differences in the rendering of the water. The DX10 river water looks more blue and the quality of the cloud reflections off the water is, in my opinion, identical. In fact, my own opinion is that the river looks more realistic in the DX9 graphics than in the much hyped DX10 graphics as, of course, river water shouldn’t look blue it should look more brown or dark gray (as it does in the DX9 image). The clouds look identical between the two images as do the various features of the landscape.

Here is another pair of images (below) this time taken much closer to the ground and showing a runway and some taxiways.

DirectX 9 (Click here for original image, 6.6 MB)
DX9 Image

DirectX 10 (Click here for original image, 6.6 MB)
DX10 Image

All of the comments from the previous image pair also apply to this pair. Once again, the river water appears a bit more blue in the DX10 image and again I don’t think this accurately reflects what a river looks like in real life. In this image pair you’ll also notice one major difference in the form of rendering issues with bits of the taxiway appearing on the runway at the taxi / runway intersections. This is something that has been widely reporting by many, if not most, users of DX10 in FSX. Forums are full of fuming users who say that, because of this, they feel the DX10 graphics are worse than the DX9 graphics. It’s difficult to appreciate the effect from a still image and hence I’ve prepared a video side-by-side comparison showing the much complained about ‘flickering’ of DX10 runway and taxiway graphics in FSX (below).

Flicker, flicker flicker…
As you can see from the video this flickering effect can be very annoying, particularly while taxing. After a few minutes, it’s enough to give one a headache. This DX10 flickering bug in FSX doesn’t seem to effect some airports, but it’s present enough to be a major annoyance. Another unfortunate symptom of these DX10 issues is that the progressive taxi fails to display properly.

Whether this is a software (FSX) issue or a hardware (GPU driver) issue is a subject of debate and, at least at the moment, there doesn’t appear to be a fix available. Microsoft seems to be keeping quiet despite much discontent from their users over this serious issue. DX10 hardware was on the market and in use long before Microsoft released DX10 for FSX and thus therefore, in my opinion, it was (and still is) Microsoft’s responsibility to ensure that their software worked with the existing hardware. I really, really dislike when much hyped features get released only to find that they were woefully untested… and this wasn’t exactly something that was hard to miss!

Oh dear, so is it all just bad then?
Well, no… there are some positive aspects to DX10 in FSX. Most notably is performance. Although there’s essentially no overall improvement in the quality of the graphics in many cases there will be a noticeably improvement in the performance, in frames per second (fps). Obviously, every system is totally different and thus it’s impossible to predict how DX10 will fair on your own system. However, in my own informal tests I found anywhere from a 20-40% performance increase in graphics rendering. For example, if I’m getting an average of 22 fps at a particular location then I might get an average of 36 fps in DX10 (with all other settings the same). This can, in many cases, make a big difference.

However, the catch is that fps performance is generally only stretched close to the ground during taxi, takeoff and landing. At altitude, if you’re already getting 40 fps then any performance increase won’t really be that noticeable (although I certainly appreciate that some users struggle with fps even at altitude and thus may still see improvement there too). Therefore, although there may be a higher fps around the airport, the previously described rendering issues with ground textures ruin any appreciation of increased performance. What’s the point of some extra fps if the taxiway markings flash like a disco strobe?

In summary, the good and bad…
In many regards, Microsoft really blew the introduction of DX10 into FSX. The graphics never lived up to the pre-released hype and those that ventured into the world of Vista (perhaps, like myself, lured in by the promises of DX10) to enjoy these new features were left with buggy flickering graphics. Instead of using DX10 to produce a noticeable improvement in graphics, it appears instead that the more efficient DX10 was simply used to render the previous FSX graphics a bit faster. Although this increase in performance is certainly a big plus, the benefits are largely offset by the other problems that everyone’s experiencing.

What’s good about DX10 in FSX?
– I did notice an impressive increase in performance, in terms of fps.

What’s bad about DX10 in FSX?
– It came nowhere near living up to the pre-release hype. A side-by-side comparison shows the quality of graphics between DX9 and DX10 FSX to be nearly identical in most cases.

– Jitters and bugs. There are widespread reports and complaints regarding various bugs and compatibility issues with DX10 FSX. The most annoying of these is in the form of horribly flickering ground textures on taxiways and runways.

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9 Comments on “DirectX 10 in Microsoft Flight Simulator (FSX) – Amazing graphics or a load of hot air?”

  1. Ciderman5

    Nice overview. I have tried DirectX 10 with FSX and have experienced the same issues that you and other have described. The flickering is very annoying! I can’t believe they released the DX10 implementation without spotting that. Unbelievable. Anyway, hopefully it will be fixed soon!

  2. jd5

    Ditto. The whole gaming community has issues and complaints over DX10 so us Flight Simmers are certainly not alone!


  3. Nice article!.

    I’m astounded at the fact that you do seem to have actual buildings in dx10. Mine look like this

    http://home.planet.nl/~plum0029/fsxdx10hooray1.png

    And that came from a clean install.

    Since MS is already busy with their next flightsim (that will run fluently on computers from 2020) I’m afraid a patch won’t be forthcoming. It’s very silent on fsinsider and related ms sites….

    Did you test any of this with SP1 on vista btw?

  4. Austin McCall

    Ditto to all. I agree. I’ve had the SAME problems.

  5. Nabeel

    I’ve been running alot of benchmarks, with some interesting results.
    Email me, I’d like to get your opinion!

  6. nini92

    direct x 9 is fine for me.

  7. Robert Vertalics Sr.

    OK ALL!!! It is 07.17.08 and no fix in site yet!!! One of the reasons I purchased a new Vista based system was DX 10. Since I use FSX and X-Plane … What a big disapointment it is … I’ll bet that MS will fix this problem in the new FS what ever but it will cost us bucks to get it. I DON’T THINK SO!!! Good luck simmers – we’ve been taken again Bob

  8. Bjornke

    I also nopticed that my GPU is very capable of producing 8X Antialising in DiectX9 in FSX


  9. This is especially important if you are a FSX Pilot that flies for Virtual Airlines and needs to see good graphics!

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