I've noticed that framerate is extremely low, rendering the game unplayable.
The more 2D elements on the screen (HUD, menues, etc) the slower the framerate is. When the title screen is showing framerate is below 10 fps (measured with Fraps). While gameplay, 24 fps, but on cutscenes, when HUD disappears and the screen is 2D-element-free, framerate soars to 85 fps (vertical sync maximum), dropping to 15 fps everytime dialog lines appear on the screen.
My system specs:
PIV 1.8GHz
1Gb RAM
Ati Radeon X800 XT, driver version 6.14.0010.6806
Realtek AC97 Audio
DirectX 9.0c

I had same problem, but i switched my two graphic card from sli to single mode and game works exellently.

I have the same problem and it's really annoying . It's making the game unplayable for me. :(
I notified the gog team a month ago and I've yet to receive a reply. Anyone else that has a solution?

Now that I just dove into the modern world of Linux face-first and made sure to get that free copy of CrossOver Games while they were giving them away for that Lame Duck Challenge, I decided to try out Sacrifice under Ubuntu 8.10 Intrepid + CrossOver Games 7.1.2 just for the hell of it.
Ironically, it runs BETTER than under Windows Vista x64 when there's tons of 2D elements on the screen. No concerns about framerate, that's for sure! (Unfortunately, I can't make use of EAX under this environment, whereas I have ALchemy under Vista.)
I doubt that you're going to install a new OS and set it up just to run Sacrifice with better performance, though. (If only I knew a way around the slowdown myself...)