dual monitors on a radeon 9000

i have been running 2 x 17" adi monitors @ 1024 x 768 @ 75 htz on the radeon
9000 card no problems. have just got hold of 2 x 19" dell P991 trinitron
monitors that i'm running @ 1280 x 1024 at 85htz,the monitor that is
connected to the dvi socket via the dvi to analog converter seem to go in
and out of focus very slightly, noticable on web pages with lots of writing
ie news groups and similar. i have swapped the monitors round so don't think
it can be that as they both appear to exhibit the same problem. i am using
the latest catylist drivers was hoping that someone might be able to point
me in the right direction. could it be that the radeon 9000 is not up to
running these monitors at this refresh rate and resolution i know that the
9000 is a couple of years old but was hoping it would last a little longer