Saturday, December 15, 2007

I will reply (soon)

At this point my in-box has approximately 180 emails from the month of December regarding X-Plane 9. So while I appreciate all of the feedback we've gotten (bug reports, performance, etc.) it's going to take a while to reply. If you haven't heard from me, don't panic! I hope to answer a whole pile of emails next week.

In the meantime, I've been working on improved crash logging on Windows. Right now when we have a crash on Windows, all we know is that (1) X-Plane crashed and (2) what DLL we crashed in (which is always us or the video driver - not useful).

Coming soon, X-Plane will catch the fatal crash, examine memory to see what was going on, examine its own EXE to figure out the names of the functions going on, and output it all to a crash log that users can send us to get a much clearer picture of what's going on. This information is called a "backtrace" - we've had it for the Mac or a while (OS X provides back-traces automatically with a crash) and it's really useful.*

So my top priority is all of the users who are seeing problems during scenery load, and a new build with a back-trace should help to reveal what's really going on.

I'm also working on putting additional timing and performance information into the sim so we can learn more about why some users have poor performance. So far here's what I'm seeing:
  • 8800 users seem to have great performance. If you have this card and don't have good fps, adjust your x-plane settings and NV control panel settings - this card can bring it.
  • 8600 users sometimes have performance problems - not sure why.
  • Older nvidia GPUs (7600, 6800) sometimes have performance problems with the new eye-candy features - I am investigating.
  • The pixel shaders seem to slow down the new HD2x00 Radeons a lot more than expected...I still need to investigate this. This is the most surprising datapoint - the X1600 does very well, so I would expect newer GPUs to at least have that level of performance. I think this is something we might be able to address.
However not all of the reports are consistent, so I think it's too soon to make some calls on recommended hardware. The only thing that's clear is that most 8800 useres who we do careful perf experiments with end up with huge framerates.

* Microsoft provides some back-trace facilities, but since we don't use their compiler tools, we had to roll our own.

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