> If my system bus is limited to 66mHz (beige G3) is it pointless to > buy an ATA100/133 card?
>not pointless at all. i believe the ata channel is only 8 bits wide, >while the pci bus is 16 or 32 (i'd have to look it up to know for sure), >which means 66mhz at a 2 byte width is the same as 132 mhz with one byte >data width. if the pci bus is 32 bit then it's like a 264 mhz 8 bit >path. so actually, the bus can still keep up with the card, at least in >theory. Very close, PCI bus runs at 33MHz (speed) X 32bits wide = 132MB/s. SYSTEM bus can run at 30, 33, 40, 50 or 66MHz (older Macs/PCs) or 100/133MHz (newer Macs & PCs) but by definition PCI *SHOULD* be 33Mhz and (theoretically) 132MB/s. ATA133 will benefit if connected to HD of same flavor, even though no drive could feed the monster, the transfers from HD cache to memory will be much quicker freeing the PCI bus and CPU for other tasks (remember, SCSI has low CPU utilization IDE still needs the CPU for I/O coordination.) RAID particularly benefits from faster transfer--SCSI has gone to 320MB/s transfer primarily to speed RAID arrays (my U160 SCSI RAID equipped server blows the socks off of everything else I've seen.) In addition, cards and drives with ATA100/133 will tend to have newer designs and components with improved performance. Also, each Master/Slave pair will run only as fast as slowest drive on the cable, so don't mix ATA drive speeds if at all possible. EricB -- G-List is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- We have Apple Refurbished Monitors in stock! | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> G-List list info: <http://lowendmac.com/lists/g-list.shtml> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/g-list%40mail.maclaunch.com/> Using a Macintosh? Get free email and more at Applelinks! <http://www.applelinks.com>
