Split Audio and Video?

I just finished an 844/x install and was informed that the Audio and Video should be captured to different drives. Now, FCP/Cinewave systems used to have it this way around early 2003. Then I was told that all to the same was fine. Is this still the way "everyone" else does it? Or should video go to the raid and audio to one of the Internal drives in my G5?

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G5 DUAL2, 10.3.4, FCPHD, CINEWAVE 4.6/33, ATTO UL3D, QT6.5.1, RORKE DATA 4X73 w/10K Seagate