I used to run a DC250 with EFI bustled RIP and the lineart was razor sharp.
The only time I had a problem like yours was with system software v.1.0 but an update to 1.1 fixed it. That said, try changing Fiery settings: enhanced line/text on/off, trapping on/off and also try changing screening settings to line from dot.
The gradients were not so good - sometimes you couldn't get them right because the line screen, in my opinion, was too high.
Now I have a X700 with Creo and I just printed a customer supplied PDF with gradient from one end to the diagonal other end (42 cm) - perfect!
The only time I had a problem like yours was with system software v.1.0 but an update to 1.1 fixed it. That said, try changing Fiery settings: enhanced line/text on/off, trapping on/off and also try changing screening settings to line from dot.
The gradients were not so good - sometimes you couldn't get them right because the line screen, in my opinion, was too high.
Now I have a X700 with Creo and I just printed a customer supplied PDF with gradient from one end to the diagonal other end (42 cm) - perfect!
