gramboh brought up the right point. This is not always an issue but happens often. This example would be better if we knew the Hard Disc Drive(hdd) DanK414 was using. Lets assume it's an ata-100 hdd the Ultra DMA mode would be 5. An optical drive(cd/dvd) has a speed of ata-33 or UDMA mode-2 or possibly Multi-Word mode-2. Putting both devices on the same ribbon can make them both run at the lower speed. You should know this within several seconds of Windows starting to load after booting. It will be slow and the drive will make more noise with longer read/writes than normal.
You can comfirm what mode the drives are running in by going to System Properties by right clicking "My Computer" in the start menu, then click the hardware tab, then click device manager, expand the IDE ATA/ATAPI controllers by double clicking it, double click the Primary IDE Channel, Click the Advanced Settings tab. You will see the speed in the Current Tansfer Mode field of each device. "DMA if available" should be selected in both the Trasfer Mode fields.
If the fields are not correct there really isn't much you can do resolve this if you have the jumpers set correct and using the right IDE ribbon. You can switch the drive on the ribbon making the oppisite drive the slave. I have no Idea why some systems select the correct speeds and some don't. I guess it has to do with compatiblity of the componets and/or chipset.
If that doesn't improve things your option at this point is to buy a Sata to IDE adaptor/converter and use one of the Sata channels. I have three of them they work well and do improve performace no matter what someone may tell you. I can't remember in my case but there is a chance you may have to reinstall XP. I honestly can't remember.
Depending on the controller the board runs the Sata from will determine if you have to do a Repaire from the XP disc and install the third party boot device drivers. It would be wise to copy the Sata drivers to the root drive(C:\) before installing the adaptor. Someone that owns the board may know a little more about the Sata drivers. If Sata is ran from the chipset then the drivers are probley included in service pack2 of Windows XP.