Just my feedback about your original Roland question and latency:
I’ve a Roland TD12 as well with RME Fireface 802 audio interface (Firewire). I use Windows with Reaper and SD3 samples located on a normal 7200rpm harddisk, Intel Core I7.
My smallest possible buffer size is 64 Samples on 48kHz sample rate and no clicks and pops with SD3, but never tried this with SD2. This is similar to:
Output latency: 2.8ms
Buffer latency: 1.0ms
This is extremely good compared with other audio software which requires most of the times larger buffer sizes.
In a normal recording setup I always use 128 samples, 48kHz in Reaper with SD2 or SD3. Then it is also possible to add additional effects outside SD. This is similar to:
Output latency: 4.8ms
Buffer latency: 2.7ms
To be honest, I don’t hear/feel the difference between 64 or 128 samples.
For mastering I always use high buffer sizes such as 1024 samples where latency does not make sense.
My conclusion:
– SD3 has a very good performance and impossible to hear latency which makes it ideal for E-Drum recordings and playing live.
– An SSD decreases loading time at startup compared with a HD, but has no effect on playing when it’s loaded in RAM.
– Additionally, the whole repsonse of the kits in SD3 is much better, including the HH control. The dynamic range of the new kits is much better, even with a clean kit without any effects. I wish SD3 was 10 years earlier available.
I can’t say anything about MAC. Maybe this is helpful for others… 
