Photoshop CS5 Strange Lag--Delayed Response

Question

Hello, Im having a peculiar problem with my Photoshop, it is lagging. But let me explain.
When I draw a line, I cannot see it.
However, if I draw a second line, I can now see the first, but not the second.
If I draw a third line, I can see the first and the second, but not the third.
Or sometimes I will see the line as I draw it.
But if I hit undo, nothing happens.
But if I draw a second line, the first will disappear.
I will decide to make layer 1 invisible. But I can still see it even though the visibility icon is off.
But if I zoom in or out, suddenly layer 1 is not visible.
It is not just a simple lag, because I can still operate, it's not frozen. But it also doesn't matter how long I wait, it won't catch up unless I take some form of action.
It seems like the program knows what is happening, and is recording it as such, but it isn't showing me.
I'm very sorry, I tried to look this up, but I couldn't seem to find the answer.
Mac OSx 10.6.2
Processor: 2x 2.26 GHz Quad-Core Intel
Memory: 12 GB

Answer 1

>> Mac OSx 10.6.2
That's part of the problem - you should be on 10.6.8 to pick up a ton of bug fixes.
And if you meant 10.7.2, then you'll have to wait for Apple to fix the video card drivers.
In the meantime, you can try disabling OpenGL drawing to avoid problems in the video drivers.