Wednesday, March 31, 2010

OS X 10.6.3 Performance

OS X 10.6.3 is out. Besides adding a bunch of OpenGL extensions*, it looks like vertex performance is improved on nVidia hardware. My quick tests compare 10.5.8 to 10.6.3 (since I no longer have a 10.6.2 partition) and show a 15-30% improvement. If you have 10.5 and an 8800 you may want to consider updating your OS.

I also discovered that --fps_test=3 produces unreliable results because...wait for it...the deer and birds are randomized. If they show up during the fps test, you get hit with a performance penalty. I am working to correct this and may have to recut the time demo to work around this behavior.

If you are trying to time the sim via --fps_test=3, I suggest running the test multiple times - you should see "fast" runs and "slow" runs depending on our feathered and four-legged friends.

Phoronix reported a performance penalty with the new update; I do not know the cause of this or whether the fps_test=3 bug could be causing it. But their test setup is very different than mine - a GeForce 9400 on a big screen, which really tests shading power. My setup (an 8800 on a small screen) tests vertex throughput, since that has been my main concern with NV drivers.

My suggestion is to use --fps_test=2 if you want to differential 10.6.2 vs. 10.6.3. I'll try to run some additional bench-marks soon!

EDIT: Follow-up. I set the X-Plane 945 time demo to 2560 x 1024, 16x FSAA, and all shaders on (e.g. let's use some fill rate). I put the Cirrus jet on runway 8 at LOWI, then set paused forward full screen no HUD. In this configuration, I see these results:
Objects  10.5.8   10.6.3
none 85 fps 100 fps
a lot 46 fps 61 fps
tons 37 fps 42 fps
Note that in the "no objects" case the sim is fill-rate bound - in the other two it is vertex bound. So it looks to me like 10.6.3 is faster than 10.5.8 for both CPU use/object throughput and perhaps fill rate (or at least, fill-rate heavy cases don't appear to be worse).

* These extensions represent Apple and the graphics card company creating software interface to fully unlock the graphics card's abilities.


garrettm30 said...

Thanks for clearing this up. I had run across that Phoronix article and posted about it on

I am curious if the new extensions or updates to OpenGL in OS X will be of any use in X-Plane for current hardware, other than the performance improvements you have already mentioned.

Benjamin Supnik said...

New extensions - not necessary for v9, but useful for many next-gen rendering engine improvements.

PIerre-Olivier said...

Yes, but the real question is :

For a 10.6.2 X-Plane user Does it make sense to upgrade to 10.6.3 ?

I'm in this case, and I'm enough penalized with the the poor quality of video driver (Mac Pro + 8800), and don't want to loose anything in fps.

Benjamin Supnik said...

One brave user should take fps tests, update, take more fps tests..then we'll know!