Saturday, December 08, 2007

Cores and Drivers and Vsync

Random thoughts:

Update your drivers! Version 9 uses driver features that version 8 does not. Just because version 864 works doens't mean that your drivers are up to date and bug free! First thing to try when weird things happen in version 9 is a driver update.

If you have 60 fps and a rendering setting cuts it to 30, you probably have vsync on - that is, your graphics card can only run at an even divisor of your refresh rate. The next hit will be 20, then fog. Change your monitor refresh rate to 75 or 80 hz. If the framerates all change (to 80, 40, 20, etc.) it must be v-sync. Turn v-sync off for better framerates under heavy load. Nvidia users, you need to turn v-sync to off, not application controlled.

X-Plane 900b7should be able to put sustained load on three cores - if you're recording a QuickTime movie, one core draws the world, one compresses QuickTime frames, and one rebuilds 3-d as you fly. So...I guess we've already hit a point where a quad-core machine has some benefit over a dual-core machine. (I think we'll start to see more central features use more cores during the v9 run.)

The new forests rebuild 3-d very frequently - dual core users who run on "tree hugger" should see utilization of 75% or higher on both cores, depending on video card power. (If your CPU usage isn't 100% then probably your video card is holding you back - turn down FSAA.)


Anonymous said...

This is GREAT news. I bought my new computer just so that I could run x-plane 9 and future versions. To read that x-plane is using 3-4 cores is perfect- this is just what we want to see. With quad-cores being almost for free nowadays parallelization really is the right way to go! For this you earn a special thanks!! Now, try keep up with the parallel thinking and make future features able to split on 4, 8 or even better - n cores!

Alejandro Garcia said...

s waiting for a new PC for V9 and was thinking about a dual core but reading your post I'm now thinking about buying a quad core

thanks Ben