Under the best of hardware, 3D painting can be slow. My guess is that if you are using a 32bit OS you are also not using a very current GPU or CPU. There's a good reason there were not a bunch of 3D painting apps 10 years ago, though there were a dozen 3D modeling/animation apps - power. I don't believe it would be of any interest to the company to develop a 32bit version for such a rapidly disappearing market.
I'm sorry Unity2k, but that does not answer my question.
As for my OS (maybe I should have been more specific?), it's a vista and my hardware is as follows: GPU, NVIDIA GeForce GTX 260.
CPU: Intel core duo 3.00GHZ 4G RAM.
I run Substance Designer 4 and Zbrush fine on it.
As for it being a dying market etc... That's a non-answer and not what I asked. Frankly I find it rude and bordering on condescending.