Not sure about any changes with the new patch, but when I was running 1.0, I had some luck with enabling SLI in order to get more performance; I had to set it to "Alternate Frame Rendering 2" in the SLI settings tab in order to get it to benefit instead of hinder me, but it was a great improvement on FPS. CPU/RAM usage was minimal, and I can tell you that they did a good job optimizing this game CPU-wise, because it uses all 12 of my threads pretty equally. The poorly optimized parts of the game seem to have to do with applying post-processing to large numbers of polygons in a scene, because framerates always tank when I have lots of FX on and I'm trying to run through a crowded area (lots of NPCs = lots of polys). GPUs hit 100% usage quite easily when that happens.
The best way to reduce FPS is therefore to lower the city population (it's an option, but I forget what it's called); this will reduce the amount of polys the GPU has to apply FX to. Alternatively, you can lower the FX - AA in particular is always a good candidate for turning off. Which of the two methods is less immersion-breaking depends on the end-user, of course.
Here's my crucial system specs, FWIW:
CPU: Intel Xeon W3680 ES @ 4.0ghz (OC)
RAM: 16gb 1333mhz dual channel
GPU1: EVGA Nvidia GTX 760 SC 2gb
GPU2: EVGA Nvidia GTX 760 2gb
Game HDD: 250gb SATA II
OS storage: 120gb Patriot Blaze SSD running in SATA II.