PCI Latency Timer

[tysfamily]

In CMOS of my new MSI MB and ASUS MB it have the PCI Latency Timing set at 64 , but I'm sure that my older computers are set at 32. I'm not sure of this one, what should this should be set at? I'm running Windows 98SE and my VGA cards for these computers are PNY FX5600 Ultra DirectX 9C and ATI 9700Pro DirectX9C. I don't want to Overclock I just don't want the system to crash or lockup. I've had major probulm with the VGA crashes in the MSI 865PE Neo2-PFS Platinum Edition and the SOYO SY-KT600 DRAGON Plus. Any help would be great, thank you for your time.

[SolApathy]

Normally, the PCI Latency Timer is set to 32 cycles on most machines. (but this varies depending on the manufacturer of the board) This means the active PCI device has to complete its transactions within 32 clock cycles or hand it over to the next PCI device.

For better PCI performance, a longer latency should be used. Try increasing it to 64 cycles or even 128 cycles. The optimal value for every system is different. You should benchmark your PCI cards' performance after each change to determine the optimal PCI latency time for your system.

But you need to remember that a longer PCI latency isn't necessarily better. A long latenc can also reduce performance as the other PCI devices queuing up may be stalled for too long. This is especially true with systems with many PCI devices or PCI devices that continuously write short bursts of data to the PCI bus. Such systems would work better with shorter PCI latencies as they allow rapid access to the PCI bus.

In addition, some time-critical PCI devices may not agree with a long latency. Such devices require priority access to the PCI bus which may not be possible if the PCI bus is held up by another device for a long period. In such cases, it is recommended that you keep to the default PCI latency.