Lag when painting textures

Hey, everyone, I am attempting to paint textures for my first sculpted head in blender 2.57 and am having difficulty because the brush keeps lagging. The head is only 946 faces with a high res head baked into it. Are there any settings I can adjust to make the painting run more smoothly? Or is my computer just too slow? I am using a three year old windows vista 32 bit lap top. Its got dual 2.10 GHz processors and the graphics card is a GeForce 8400 GS (if that helps people who are more knowledgeable about hardware than me) .

Let me know if you need any more info

Thanks so much

it should be smooth as butter. what is the resolution of your image file that you are painting to? are you in multires mode?

I had the same problem some time ago. In my case the solution was to take an image with dimensions which are a power of 2 like 512x512 or 1024x1024 and so on. Hope this can help you.

Ahhhh I see. The image is 3060x2048. However, if I change the x and y to be the same number the painting speeds up incredibly. So if you are having the same problem as me make sure its 2048x2048, for example, and not 2048x3060 or some other number