I have a 40 Gig 7200 RPM ATA133 hard drive. My question is: Does putting an slower device like an ATA 33 CD ROM drive as slave on the same IDE cable really reduce the performance of my hard drive (ie its transfer rate, etc.)? Please comment.

it shouldn't. The cd-rom will probably be kind of slow. The only time the HDD will be slow is when it is accessing the cd drive. mark

Most modern hard drives are either ATA66/ATA100/ATA133. Most modern CD/DVD/CDRW's are either ATA33 or slower. Two drives on the same IDE channel work at the speed of the slower drive, so putting an ATA133 hard drive on the same IDE channel with a ATA33 CDRW WILL SLOW YOUR HARD DRIVE TO ATA33 speeds, thus slowing your system. Mixing devices of different speeds on the same IDE channel is one of the biggest mistakes made by DIY system builders.

Who to believe? I don't know. If you only have the two drives, I guess you should put them on their own channel. So UTLLAMA, what you're saying is you have more than 3 drives (i.e. a fast HD, a slow HD, a CDRW, and a DVD-ROM lets say) my faster harddrive is gonna be screwed speed-wise, unless I get an extra ATA card?

I work for a motherboard MFG. The latter is true. Your speed will be ata33 if you combine the two. What I have done is use a motherboard with RAID onboard. I can use the RAID as ATA 100 IDE channels. My 2 HDD's and my CDROM and rewritable are all on their own channels now.

Which MOBO company is that 'I help U', just so that I make sure never to buy one of their products: or another board that uses the same chip sets. The performance of an individual IDE device is not affected by another: unless of course they are both attempting to transfer data simultaneously.

Intel - Oregon And if you put an ATA 100 HDD on the same IDE cable as your ATA33 CDROM, your speed on that channel defaults to the lower speed. Here, this will help. http://www.mikeshardware.com/howtos/howto_connect_ide_hd.html http://support.intel.com/support/motherboards/desktop/vc820/assembly.htm#ide