I have a 2000FP hooked up to my 4600 and I don't have any problems like you're describing. I use 1152 x 864 at 32-bit with a refresh rate of 75 hertz. I also have a 9800 pro vid card.
Don't know about refresh rates not impacting display quality on an flat panel but when I moved mine up to 75 hetz things seemed better.
But mine is connected through analog rather than the digital output. I tried the digital output but had some problems and not enough time to futz with it. In the long run though I need to use analog as I have two PCs connected to the monitor through a KVM switch. My other PC (business) does not have a digital capable card.
Have you tried running the monitor on the analog output? Is there a difference in the quality? Supposedly digital is better but I've read about other people having problems with the digital output of their cards.
I'd try it with another computer or video card. I suspect the card. I've had mine almost a year with the ATI 9700pro and it's as sharp as ever..no problems. It usually only represents what the video card/driver sends to it. Good luck.
100% OEM....Dimension 8250 ...BIOS A04, Office XP Pro, XP Pro sp-1, 1.5 rdram 1066, 200hd,1800fp, IBM 8514, IBM Model 70, audigy2, ada 995's, 9700pro, HP d145, Laserjet III, 16x Lite-on 163, 4x Nec 1100a.
It worked fine before I fixed it![:$]
Precision Tower 5810, Quadcore Intel Xeon E5-1630 v3, 3700 MHz
RAM:16 GB PC6400 DDR4 SDRAM 1066MHz
HDD: 2x ATA ST500DM002-1BD14 500GB SATA non RAID
DVD:HL-DT-ST DVD+-RW GTA0N SCSI and PLDS DVD+-RW DH-16AES SCSI
Video: nVIDIA Quadro K4200 PCIe 4GB
Audio: Recon3D PCIe, Altec Lansing ADA995 5.1 speakers
Monitor: Dell E2011H