Wednesday, September 05, 2007

How to Make X-Plane "wicked fast"

Here's a hack that you can do to make X-Plane a lot faster: switch back to ENV scenery.

Okay, this is a completely ludicrous statement, but ... if I take X-Plane 860 (default settings) and turn off birds, cars and high detailed world, then view runway 6 with no panel, I get 45 fps with DSF vs. 83 fps with ENV. Load times are also faster too - the KSBD tile takes about 3 seconds to load vs 0.22 for the ENV.

Now of course you wouldn't want to use the ENVs if you've used the global DSF scenery -- even on the most simple axis the DSF scenery is superior, with typically around 150,000 to 300,000 triangles per tile rather than 60,000 in an ENV. (There's a lot more going on in a DSF than just that.) So ENVs are a lot faster because they do a lot less. You get what you pay for.

Just for fun I tried running X-Plane "7.0 beta 0", which was sort of a 7.0 preview, really more like X-Plane 6.70. It runs at about 85-90 fps. But it turns out that you'll get the same thing out of X-Plane 860 by replacing the new bezier-curve-based runway layout with the old simple square one. I also noticed that there are no runway shoulders in 7.00b0. It does beg the question: while I tried to set them up as similarly as possible, how man other things is X-Plane 860 doing that we just don't notice, but that cost fps?

I mention this in the context of the hardware requirements for future versions of X-Plane. We do sometimes raise the hardware needed to use X-Plane by putting in more graphic detail (that consumes more hardware) and not providing a fallback to the old way X-Plane looked. But I think what creates the sense of "I need a new computer" even more is how tempting and desirable the new technology is compared to the old.

When you look at computer performance in a given market, additional computer performance translates into additional usefulness up to a certain point. Past that point, the additional performance is worthless. This drives the price/performance ratio of the entire market -- you can see it with desktop computers.

It used to be that desktop computers cost $1000. Then we hit a day when all new computers could word process, send email, and surf the web with no trouble. At that point, buying a faster computer is pointless, and thus computers started to drop in price. This makes companies like Intel fairly unhappy.

But the flight sim world doesn't have this problem yet - every bit of new computer performance can be invested in more realistic graphics, something that there is clearly an appetite for.

In this context, my concerns will always be:
  • Efficiency. For the same hardware and graphics detail, is the framerate getting better, or at least not worse? (Previous comparisons of 8.60 with 7.63 show 8.60 to be faster with ENVs...I think that 7.00b0's apparent speed is because it's missing a ton of features that the version 7 run introduced.)
  • Lowest config. How far down can we strip the graphics to let users with older hardware keep playing with the most recent airplanes and features?
  • Highest config. How much hardware can we soak up and convert to graphics detail? Are users with the newest systems getting their visual "money's worth"?

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