MASTER SLAVE EIDE PERFORMANCE ISSUES

[polycue]

Current config:
3 HARDRIVES PLUS 1 CDROM
2 - 10 GB Western Digital 7200RPM DMA
1 - Maxtor 40GB 7200RPM (incoming) UDMA
1 - CD-ROM (HP CDWriter (HP8100))DMA
Asus P2B Motherboard
PII-450

What kind of performance issues can I expect by having the hardrive as master and the CDROM CDWriter on the secondary channel?



[This message has been edited by polycue (edited 20 February 2000).]

[polycue]

ADAPTEC: If you have a Pentium PCI-based system:
If the motherboard has Bus Master IDE ports, we recommend that you disable UltraDMA for the IDE Channel that the writer is on.



[This message has been edited by polycue (edited 20 February 2000).]

[RAB]

PC World has some information on DMA and CD-RW's in this month's issue. You can also get it online <a href="http://www.pcworld.com/current_issue/article/0,1212,14877+10+0,00.html">here</a>. But just know that the DMA setting of the drives you have on the same cable is often the cause of problems, so proceed with caution. BTW, the PC World article says that the HP 9110 they reviewed worked best with DMA turned on.

RAB

[polycue]

You wrote: Just a few thoughts:
1. If your new Maxtor is a UDMA66 drive and your board does not support this, you will need to download Maxtor's patch to keep the HD in UDMA33 mode. This way the bios will treat it as UDMA33 and it should run smoother. A motherboard bios upgrade can not make an older chipset recognize UDMA66 - that has to be built into the chipset.
2. I would install the Maxtor as the primary and the DVD as the slave. Some HD's like this and others don't care. I have a Maxtor too, but I've never tried it as a slave.
RAB

Have you tried a UDMA66 as master with a CD Writer as slave? Is it possible to run this configuration with the HD at UDMA and the CD-RW at DMA with no performance hit for either device?


[This message has been edited by polycue (edited 20 February 2000).]

[RAB]

The ASUS board you have has a BX chipset which does not directly support UDMA66. If you want to use UDMA66, you need a Promise card. Otherwise, it would be best to download the Maxtor patch to keep your HDD running in UDMA33 mode. (Since I don't have a BX board, someone correct me if I'm wrong on this, but I think I'm correct.)

AS far as running your HDD and CD-RW on the same cable, it should work fine. I've got a Maxtor UDMA66 and a Toshiba DVD-ROM UDMA33 both on the same cable without any problems. Sorry, but I don't have a CD-RW yet, so I can't answer your question from experience . Normally, I would keep DMA similar devices on the same cable. For some reason I don't understand, I got better measured performance from my HDD with both devices on one cable and the other IDE channel empty.

Since you have four devices, you won't have the luxury of experimenting with leaving one channel unused. But still try the Maxtor (using UDMA33) and the HP (using UDMA33) on the same cable. It should work.

To see what your drives are cabable of, watch the second page of the bios screens when your computer starts up. If it uses an Award bios, it will list the devices and their DMA modes. Match whatever it says in the list in your Device Manager. Try not to mix UDMA and PIO mode devices on the same IDE cable.

RAB