Slow DVD read/data transfer?

[hangtight]

I'm hoping someone can point me in the right direction to sort out a problem with my PC.
System:
Intel dual core 6400
Foxconn MB
4GB RAM as 4 1GB sticks
New HDD
Fresh XP install
8800GTS 640MB
Samsung SH182D DVDW
LG DVD ROM

The problem I was having before the fresh XP install and still have, is put a DVD in either of the drives, and as well as very low read speeds (1GB /15mins), the processor will hit about 90% and slow the computer right down to the point where you can't watch a film direct off the disc (or do anything else useful while transfering data).
I've tried both drives individually as well as various combinations of both, there's a new IDE cable, but always the system exhibits the same behavior.
The latest firmware/ drivers for the drives didn't have any noticable affect, a search of the net hasn't turned up any answers and I've run out of ideas!

[centaur]

Have you tried disconnecting the DVD ROM and just leaving the DVDRW connnected (if there is a 'jumper' set it to 'master' ) and did this make any difference ?
You might need to uninstall it in 'device manager' and reboot the PC, allowing it to 'find' it and reinstall it again.

If this works, there may have been some conflict if the pair of them are connected to the same IDE cable and the 'jumpers' aren't set properly for one to be 'master' and the other to 'slave'.