Symptom:
When running an RTAS software sampler in a Pro Tools session at 96k, but the samples loaded in the software sampler are at a lower sample rate (i.e.. 44.1k) can cause Out of CPU error messages in Pro Tools, even with only one RTAS software sampler instantiated.

Explanation:
Most likely the high CPU load is a function of the sampler providing real-time sample rate conversion on the fly. Depending on the quality of their conversion this can account for a lot of cycles and would explain the errors. Also, at 96 kHz RTAS processing in general requires about twice the CPU power (on the host) when compared with 44.1 kHz. When streaming from disk, samples will have to be read twice as fast adding to the overall system load.

Workaround:
1) Save the Pro Tools session at the same sample rate as the samples being played by RTAS software sampler (i.e.. 44.1k). Here's how:
- In Pro Tools session > File menu > Save Session Copy In. Save session at 44.1k. Launch copied session now at 44.1k.
2) Or, possibly, convert samples to 96k before playing them in the RTAS software sampler in the Pro Tools 96k session. (If RTAS software sampler supports 96k samples).