View Full Version : bus mastering?

05-29-03, 04:20 PM

i am using an external audio/midi controller thru the USB port. I am getting random pops & clicks in the audio signal. Audio websites suggest turning off 'bus mastering' if relevant to the video card, as this feature 'hogs' the pci bus.

Q: Does the nvidia geforce2 go chip apply bus mastering? If yes, how can this be deactivated? Which driver should I be using? Are there other steps I can take to lower the chip's use of the pci bus?

any help is much appreciated!

laptop: dell inspiron 8100, P3, 1.2GHz, 380Meg RAM
Audio/midi HW: M-Audio Ozone
display chip: geforce2 go

05-29-03, 04:23 PM
Geforce 2 GO's use AGP 4x.

05-30-03, 12:15 PM
thanks. please excuse my ignorance, but does AGP 4x bypass the pci bus somehow?

are there any tweaks I can do SLOW DOWN the graphics? (to give audio more 'bandwidth' on the pci bus)

05-30-03, 01:27 PM
AGP and PCI is kinda hooked together, I don't care to explain better than that, but indeed busmastering on the AGP can affect PCI cards. So yes, turning it off could improve it for your audio card. However, I don't know how you actually turn it off, maybe a google search might help you?

05-30-03, 02:20 PM
Bus mastering allows a device to take control of the bus for more cycles than it would normally be alloted, devices like graphics cards need a steady stream of info to keep a stable display. Under certain circumstances it may need more information than it can grab in its alloted time so it masters the bus and all other data transfers are put on hold until it gives control back.

I don't think you can turn off bus mastering without a low level hack. If a card supoorts bus mastering it is enabled at the BIOS level, long before you get to windows. I also think it is a hardware feature and not a software feature.

You coud increase the pci clock latency of your graphics card but that would have a dire affect on performance.