The following chart is very handy for quickly determining sample time based on the DPM SP's RAM and the sample rate.
Sample Memory vs. Sample Time(Sample words/Sample Rate=Time[seconds])
512K @ 44.1kHz: 5.8
1MB @ 44.1kHz: 11.6
2MB @ 44.1kHz: 22.67
4MB @ 44.1kHz: 45.35
8MB @ 44.1kHz: 90.70
16MB @ 44.1kHz: 181.403
2MB @ 44.1kHz: 362.81
512K @ 32kHz: 8
1MB @ 32kHz: 15.6
2MB@32kHz: 31.2
4MB @ 32kHz: 62.5
8MB @ 32kHz: 125
16MB @ 32kHz: 250
32MB @ 32kHz: 500
512K @ 24kHz: 10.6
1MB @ 24kHz: 21.3
32MB @ 24kHz: 41.6
64MB @ 24kHz: 83.33
8MB @ 24kHz: 166.6
16MB @ 24kHz: 333.3
32MB @ 24kHz: 666.6
512K @ 16kHz:16
1MB @ 16kHz:31.2
2MB @ 16kHz:62.5
4MB @ 16kHz:125
8MB @ 16kHz:250
16MB @ 16kHz:500
32MB @ 16kHz:1000