I turn off shadows in all games, since I know how much of a performance hog it is.
Just got through an alert; as expected, it does appear to be the CPU that's the problem. Sitting in a non-alert warpgate I had about 45, 50, tagged [CPU]. Fighting anywhere was basically 10fps on top of the pixelation from the lower graphics settings I was trying to use (medium-low) to improve FPS; suffice to say, I'm pretty much useless.
I'll look at upgrading the CPU and may as well throw in as much RAM as I can while doing so, since it's going to require a motherboard upgrade as well. I know how much MMOs are generally CPU limited but I didn't think the core 2 duo was that out of date. (Not sure exactly what model it is, but dxdiag says "Intel Core 2 Duo E6850 @ 3.00 Ghz".)
Maybe I'll also get a second 660 TI throw in a larger/widescreen monitor as well (my current monitor is LCD but max 1280x1024).
I wonder if upgrading the CPU will also solve the freezing I get occasionally in PS2 and more often in RIFT. Not 100% sure what's happening, all I know is that the game kind freeze for a bit, blacks out, but then recovers. It's usually accompanied by Firefox crashing. When it happens in PS2, people start rubber banding all over the place, and the game (that is, the server) probably thinks I'm doing it too because I kept getting warnings about being in a restricted area whenever I move, even an inch, in the direction of a locked spawn point in the biolab. In Rift, actions feel like they're delayed by a quarter of a second or something, most obviously seen when I run the mouse quickly across menu buttons, where the button highlights one or two buttons "late". Now that I think of it, going to check windows event viewer next time to see if it's something graphics-card/driver related or otherwise.