That's strange.
It's the only plug-in you run in your DAW while having this huge CPU load?
Do you have this load all the time and with all Buchla sounds?
Buchla Easel V can sometimes be hard on the CPU. But this is strange to me. I run 48000 Hz at 128 buffer, and a USB buffer at 2 ms as my external soundcard has this setting availble. My total input latency in my DAW is 5 ms and the total output 7 ms. I have much lower impact on the CPU, and your CPU is better that mine i7 3770. Mostly of the time an instance of Buchla use less than 10% total CPU. It can sometimes go higher, but usually lower than 15%, and not as high as you describe. The load on a single CPU core can be higher.
Have you optimized your system and CPU settings?