It's important to distinguish between cpu performance and graphics performance. The qualcomm and samsung processor SoC's have a general purpose CPU and a dedicated graphics engine. In general...
1. Qualcomm's snapdragon cpu at 1GHz is faster than Samsung's Hummingbird.
2. The Shift uses an 800MHz version of Snapdragon. Probably a little slower.
3. The Samsung graphics engine is the Power 540. The fastest currently shipping on an SoC.
4. The Qualcomm graphics engine on Evo is Adreno 200. Shift uses new 205.
5. The Adreno 205 is much faster (4x) vs 200 and almost as fast as the 540. It also has dedicated HW decode for Flash.
So the overall user experience is based on a combination of cpu and graphics performance and response. The CPU used in the Shift isn't as fast as the Evo but it's close. Probably about the same performance as Samsung. The Shift's graphics processor is much faster than the EVO and just a little slower than Samsung. More info here:
What is Adreno 205 and how does it compare to other GPUs? - Smartphone Benchmarks (SmartBench 2010/Quadrant) Forum
http://en.wikipedia.org/wiki/Snapdragon_(processor)