PCI-bus allows the parallel operation of several devices. In such operating mode the additional buffering of reading-writing cycles is turned on in a chipset. This enables to increase the system speed but not all PCI-devices support this mode correctly. That’s why BIOS has got the parameter “Peer Concurrency” (PCI Concurrency) that points to the possibility of concurrent operation of several devices. This parameter may have two values: Enabled –the concurrent operation is allowed; Disabled – the concurrent operation is prohibited. The parallel operation of PCI and ISA buses is a special case. Use the parameter “Passive Release” to control the opportunity of such work. This parameter may have two values: Enabled and Disabled.
When you transmit data from PCI to ISA bus, there is a delay related to the significant difference in the operating speed of these buses. To speed up the system operation, use the parameter “PCI to ISA Write Buffer” that enables to write temporarily the data in a special buffer without any interruption in processor operation. This parameter has got two values: Enabled and Disabled. If this mode is switched off, PCI-bus will wait for finishing the transmission of data via ISA-bus.