otheos
10-24-2001, 12:24 PM
Currently, 32bit 33Mhz PCI bus is limited to 133MB/s bandwidth. While this is for the moment perfectly ok for home use (nothing can saturate 133MB/s on most home PC's), servers definitely require more than that.
64bit 33Mhz (266MB/s) and 64bit 66Mhz (533MB/s) are quite common to server boards. They are mainly used for SCSI adapters and gigabit ethernet.
With current SCSI interfaces at 160MB/s the 133MB/s limit is already a bottleneck (not to mention the upcoming 320MB/s). Imagine a server with 2 raid arrays attouched on a dual bus 160MB/s SCSI card. This easily totals a 320MB/s bandwidth and calls for the 64bit 66Mhz PCI bus.
Since SCSI devices are used concurrently (unlike IDE) this total bandwidth of 320MB/s is frequently saturated in real use!
All major U3W cards (adaptec 29160, LSI53C1010 based cards -like the Tekram U3W/D, and others more server oriented ones) are now using 64bit interface (usually backwards compatible with 32bit when they aim at workstation/small servers market).
Like I said, 64bit PCI is hardly a requirement for home PC's. With high end workstations and servers it is an absolute must. Like other things however, expect to see 64bit PCI (in its current form or a reincarnation) to home PC's in the future.
64bit 33Mhz (266MB/s) and 64bit 66Mhz (533MB/s) are quite common to server boards. They are mainly used for SCSI adapters and gigabit ethernet.
With current SCSI interfaces at 160MB/s the 133MB/s limit is already a bottleneck (not to mention the upcoming 320MB/s). Imagine a server with 2 raid arrays attouched on a dual bus 160MB/s SCSI card. This easily totals a 320MB/s bandwidth and calls for the 64bit 66Mhz PCI bus.
Since SCSI devices are used concurrently (unlike IDE) this total bandwidth of 320MB/s is frequently saturated in real use!
All major U3W cards (adaptec 29160, LSI53C1010 based cards -like the Tekram U3W/D, and others more server oriented ones) are now using 64bit interface (usually backwards compatible with 32bit when they aim at workstation/small servers market).
Like I said, 64bit PCI is hardly a requirement for home PC's. With high end workstations and servers it is an absolute must. Like other things however, expect to see 64bit PCI (in its current form or a reincarnation) to home PC's in the future.