Hi David,
I have the same camera, and a G5 dual 2.0. My rendered movies look great, you can see a couple at Revostock, or here: https://www.fisheyeedit.com/newstuff.html
What is your workflow? What kind of movie are you rendering to? What is your final delivery to be?
Most of my work is for SD delivery, or HD for the Web stuff as referenced above.
This is what I’m doing:
Capture native HDV (shot 30F BTW) work in ProRes timeline, render, and either scale or nest for SD, and for HD movies I render to either photo jpeg (for stock) ProRes or 8bit.
I have been having great success with the ProRes timelines, color correction, effects text with alphas, everything works great. Never caused a crash, sometimes I’ll get dropped frames, but usually an audio mixdown fixes that.
Perhaps your washed out look is resulting from a setup issue somewhere along the way. Check all your settings, including your video card if you have one.