800XT I would imagine or maybe a draw.
The x1600's were never that great even the xt but it has been a while.
Personally, I don't think any of them are worth anything right now. What are you planning on spending on these pieces of ancient history?
X1600 3.0, x800 2.0 and neither of them have any hope in hell of running crysis even at 800 x 600 resolution.
In fact they won't be able to run any modern game at anything approaching decent settings.
I have a mobility 3650 which is roughly the same level I would think and it is not much use for gaming.
However, I could be wrong, wait till someone with a better memory than I posts if you want to be sure.