I have a 9800Pro, with all settings maxed out.
Using Omega 4.9 drivers, you may need newer drivers as the ones prior to 4.1 aren't recommended (as in mostly don't work) with the perfect water.
My water doesn't look like the above though, because my CPU isn't fast enough - AMD XP 2600+ - 333Mhz FSB, 1.9Ghz, 512KB L2 cache.
In the conf.ini there is a setting that allows a lower detail perfect water (basically no land, trees, or airplane reflections) - and that is setting water = 0 at the bottom of the conf.ini.
-SW