OC pci bus and cdrom dma problem

[araaraara]

I don't use my cdrom much, so it took a while for me to notice this problem. I think it started after I raised my fsb to 75mhz with pci running at 37.5mhz. The first time I noticed it, I was trying to play a cd. It played for 2 seconds at a time every 30 seconds. I thought that maybe the drive was dead. It's a generic 36X dma2 (16.6mb/sec) drive. I messed around with it for I while until I remembered the raised but. I thought that maybe it was the problem. So I turned off dma in win98, and the drive worked fine. It is setup for dma in the bios though.
Now, I want to know if the drive is really using TRUE pio transfers now, and if so, is there a cpu and drive performance issue?

[djurom]

When you turn off UDMA in Windows it overrides BIOS setting so TRUE PIO is working. CPU and drive performance issue: Your drive will work like before but your CPU will be loaded more. CD-ROM isn't so resource intensive drive unless you use it for gaming with minimal installations so I think you'll get some performance decrease.
You're CPU is used more because all "talking" between memory and CD-ROM has to go via CPU first to allocate it.