It does sound like a re-draw issue but I'm not sure a replacement graphics card would help. Whilst your graphics card is about 5 years old, CS2 is over 12 years old so shouldn't have outpaced the GPU .
As far as I remember, CS2 did not have alternative GPU settings in Preferences ( I no longer have it installed to check) so you are limited with alternative settings.
I hope someone with CS2 installed and a similar GPU can comment and help.
Nothing to do with your card and as Dave already said, getting a newer one will not do anything. These are simply old GDI functions that more modern cards tend to emulate via their driver. You would have to extensively dig into these things and finetune them with all this double- and triple-buffering and vSync stuff and otehr things. You could spend hours on it and it may still not do anything. If you don't already, at least try running the apps in compatibility modes for Win XP or Win 7.
Thanks for your replies. I agree it would seem CS2 shouldn't be outpacing a 5 yr-old GPU. And no, I'm not seeing any specific GPU settings in CS2. I've recently read more comments as presented here regarding graphics cards having no effect on improving Photoshop's 2-D functions, only 3-D rendering, liquefying, etc, so I'm not going to spend any time trying to find a cause. I'm not a gamer and the jittery palette movement isn't horrible (just annoying) and I only move a palette here and there on occasion. I just thought it odd to only see it in Photoshop. I will try running CS2 in compatibility mode and see if it helps. Maybe I will be able to afford a newer version one of these days. BTW, I'm running Win7 Pro. Don't like 10.
I do high quality publication layout & design and I must say, the low-end GT610 has served me well for my needs. But the card is getting old and has been running 24/7, and fan longevity isn't indefinite, so may upgrade the GPU anyway.
Thanks again for the input.