Draw a antialiased line in a fast way

I have a little problem. I've recently created an algorithm to allow thick lines to be drawed onscreen (as a quad structure), the problem is that when the line is very long and diagonal the aliasing is very high, making the line look very bad. What are my chance to reduce the aliasing while trying to have high performance?

I'm using (as the tag开发者_如何学编程s says) DirectX as graphics API.

There is a very good article in GPU Gems 2 about antialiasing technique for lines, see it here:

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter22.html

GPU multisample AA will be much faster than anything you can do on the CPU or GPU yourself.

You should really try that before optimizing in a almost certainly wrong direction.