Best configuration for my IDE hard drives, DVD & CDRW?

[FOOOD]

I’m wanting to know which is the best configuration for my 2 EDIE hard drives, EIDE DVD ROM & EIDE CDRW.

Here’s what I have:

EIDE ATA 100 40Gb Hard disk

EIDE UDMA 66 20Gb Hard disk

EIDE SONY DVD ROM DDU1211 (40/12)

EIDE Yamaha CDRW CRW2100EZ (16/10/40)

My motherboard has 4 IDE ports (I can connect 8 IDE devices).
Is it best (for hard drive speed & CD writer performance) to have each device on their own separate port, using all 4 ports?
Or would it be OK (or better) to just use 2 of the IDE ports for all 4 devices?

If I just used to IDE ports I was thinking of setting it up like this (would this be the best solution?)

IDE port 1
Master - EIDE ATA 100 40Gb Hard disk
Slave - EIDE SONY DVD ROM DDU1211 (40/12)


IDE port 2
Master - EIDE Yamaha CDRW CRW2100EZ (16/10/40)
Slave - EIDE UDMA 66 20Gb Hard disk

I understand that if I had both hard drives on the same port that the ATA 100 hard disk would only run at the slower UDMA 66 (like the 20Hb hard disk). Is this true?