probably a silly question but have you included the DDBLT_WAIT flag in all your calls to Blit and Flip?
That can cause this problem, esp if your video card is too fast.

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I'm creating a Breakout clone and having a problem with the ball. When the ball moves fast, it appears to move to the current position before the previous position is fully erased causing a flickering or tracer effect.

I'm using DX with double buffering and calling Flip(). Any way to fix this?

have you used:

lpdd->WaitForVerticalBlank(DDWAITVB_BLOCKBEGIN,0);

...in your code, befor you flip your page?