Anyone successfully using BFD All with low buffers?

[j20056]

I am contemplating purchasing an 8 core Mac Pro. However, I have been having a few messages with Rail at Platinum Samples, from whom I bought the great sounding Andy Johns drum samples for BFD.
The problem I have on my current setup (PC 3GHz Pentium Duo-Core - 3GB RAM) is that BFD uses 45% of my CPU power, and I must run at 512 buffer size in order not to get the usual "H/W increase buffer size" error message. Unfortunately, 512 buffer size leads to unacceptable latency.
What Rail aid is that he runs at 512 buffer size. he also said that many record with say a Roland TD drum module to get the MIDI, but they don't use BFD during recording, only after. During recording, they use the Roland or any other zero-latency drum external module.
I really would prefer a low latency BFD based recording process, somy drummer hears exactly what gets recorded, and ideally at 128 or lower buffer size.
Is this possible with an 8 core 3Ghz Mac Pro loaded with 4GB of RAM?