exactly what does "Unknown Device" mean when you lspci? does it have anything to do with how well the device is working or is it harmless? i ask because most of devices show up as unknown and i've recently installed a new motherboard (intel 875 chipset). the computer is running really slow even after recompiling my kernel for my new pentium 4. the only modules i need for my motherboard is agpgart with 875 chipset support and my network card, right? its been a couple months since i've used linux (computer's been down) and i was a bit of a newbie to begin with, so i'm sorry for any dumb questions. thanks for any help

I may be wrong about this, but I think the unkown device designation simiply means that the drivers can't find much detail about the device and may not be using it. For example, my wireless ethernet card is listed as an unknown device because there are no linux drivers for the thing (I would like to once again thank the fine folks at Broadcom for continuing to keep their heads screwed on backwards about Linux). However the card is perfectly functional and I use it all the time through ndiswrapper. As far as I can tell, it doesn't affect performance since the computer is just as snappy whether I'm using wireless or a wired connection (which DOES have a native linux driver).

I'd bet that performance is more related to a bunch of uneeded services. Have you gone through your startup scripts and turned off the stuff you aren't using?

Your PCI IDs file must be obsolete. Grab a recent pci.ids on http://pciids.sourceforge.net/ and replace the old version with this one in /usr/share/ or /usr/share/misc/ (depends on your distrib). It can help you to find what this "unknown device" is and check your modules consequently.