Yes, generally non-RAID cards perform better that RAID cards. However, many IDE controllers have troubles in general with ODD devices (since they don't support fully the ATAPI standard too). There is a huge thread about this topic here at CDFreaks:
IDE Controllers (The definitive Thread)
From my experience, I can say is that I have a Sil0680-based IDE card (not using it now), and even flashing it with the non-RAID bios I've not been able to run my NECs (2500, 3500, 3520, 3540, didn't try with the 4551) at more than MDMA2 (while other brands were working fine). Yet Sil0680-based cards are between the most compatible IDE controllers for ODD devices...