I saw this recently and was hoping it might be of some use to video makers who are suffering video lag, jerky playback or dropped frames.
From what I can gather, if you are experiencing any of the above problems, then increasing the compression and reducing the quality say from 3.6Mb captures with 5:1 compression (DV) to 3Mb captures with between 5:1 and 8:1 compression you should still get SVHS quality.

DATA RATES AND QUALITY

MBYTE/SEC MINS FOR 1GB VIDEO QUALITY COMPRESSION
WITHOUT CROPPING WITHOUT CROPPING

21.2 0.5 Broadcast 1:1
10.6 1 Direct Transfer TV 2:1
7 2 BetaCam Digital SP 3:1
5.3 3 BetaCam SP (Pro) 4:1
4.2 4 BetaCam (Semi Pro) 5:1
3.6 4 DV 5:1 (within the camera)
3 5 SVHS Pro, Hi8 7:1
2.1 8 SVHS, Hi8 10:1
1.4 12 VHS 15:1

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DATA RATES AND QUALITY

MBYTE/SEC MINS FOR 1GB VIDEO QUALITY COMPRESSION
WITH CROPPING WITH CROPPING

18.5 0.5 Broadcast 1:1
9.3 1 Direct Transfer TV 2:1
6.2 2 BetaCam Digital SP 3:1
4.6 3 BetaCam SP (Pro) 4:1
3.7 4 BetaCam (Semi Pro) 5:1
3.6 4 DV 5:1 (within the camera)
2.6 6 SVHS Pro, Hi8 7:1
1.85 9 SVHS, Hi8 10:1
1.2 14 VHS 15:1