   Odd stuttering in basic DX application
  Greetings All,I'm working on a DX9 project that uses a basic orthographic viewpoint.Currently all it consists of (after stripping everything else out) is a simple red rectangle, and the only thing being updated every frame is this rectangle.However, despite the simplicity of the app, whenever I force a movement in a direction the rectangle shows an odd "lag", or stutter.It's as though it jerks forward then back slightly. I'm using a matrix to update the position of the object.The frame rate is around 500fps, so it's not that...The same project does this on 2 Windows installs, however it is less noticable on the faster machine. One is on a duel core system, the other a quad core...I'm baffled by this, and i'm curious to know if anyone has seen anything similar to this before.Thanks for any help,-g9   
  Try turning on V-sync maybe you are experiencing tearing because of high frame rates.   ;  Just tried changing the app to use vertical sync (added PresentationInterval = D3DPRESENT_INTERVAL_ONE) which i believe should work...However the problem is still there.More info:XP on all machines,App is windowed,tried using multiple back buffers, no help,Does this using both hw and sw vertex processing...   ;  Update:You were right, it was the v-sync.I failed to test it with another set of code enabled.Thanks for the help,-g9   