PCI lantency timer help!!!!

[fbmbirds]

is higher better or lower ? i have dual 8800gts video cards

 

[imperialreign]

changing PCI latency won't make any difference with two 8800GTS cards - as I assume they're PCI-Express.

PCI latency timings only affect PCI cards. PCIE operates at it's own BUS speeds and latency seperate from the PCI BUS.

 

[phanbuey]

latency anything means lower is better...

 

[ex_reven]

latency anything means lower is better...

not necessarily.

Going too low causes problems...

 

[fbmbirds]

i think he ment lantency any thing as of lantency being lower is always better is some cases that is true memory lantency ect

 

[imperialreign]

not necessarily.

Going too low causes problems...

I agree - usually going low with the PCI BUS causes problems in general as a lower latency lowers tha mount of time a device has access to the BUS. Typically, going a little bit higher is better, as you're giving a device more time to hold BUS access.

 

[fbmbirds]

so what should i use 32, 64, 128 ?

 

[imperialreign]

well . . . if BIOS is automatically set to 32, I tend to bump it to 64 and leave it from there . . . but, again, note that PCI latency won't affect how your PCI-E video cards will run. It will only affect PCI devices (like a sound card or network adapter, or an older PCI video card).

 

[ex_reven]

the lower the latency, the faster data is being stored and wiped from memory.

having the latency too low therefore means that you could reach a point where data is being stored and then wiped before it can even be processed. This is where data corruption and errors occur.

 

[imperialreign]

the lower the latency, the faster data is being stored and wiped from memory.

having the latency too low therefore means that you could reach a point where data is being stored and then wiped before it can even be processed. This is where data corruption and errors occur.

If we were talking about DRAM timings, you'd be absolutely correct - but PCI BUS latency is a measurement of how many clock cycles a PCI device has access to the BUS after its interupt request has been serviced. Too low of a PCI latency setting, and a device might not have enough time to transfer it's alloted amount of information back and forth across the BUS, whereas a higher setting allows a device more access time to the BUS before it's cut off.

Setting PCI latency too high leads to an unstable system, as a device will have a longer access time, and until that alloted time is up, or the system reachs the master PCI cycle, all other device interupt requests are ignored.

 

[francis511]

256 / no. of devices = latency or maximum value that is wise

 

[fbmbirds]

no of devices? i have dual 8800gts and a sound card?

 

[imperialreign]

you have 1 device, then - the sound card.


But don't go setting your PCI latency to 256!

64 will be just fine.


I again re-iterate - increasing the PCI latency will not affect your video card performance.

 

[fbmbirds]

what should i set the setting to then 32 64 9? 128