Usually i deploy mainly IBM servers that use broadcom network cards and i swear i've never encountered any problems with such cards. The other day i was asked to setup a small pc with two sata disks (in raid1). I was sure that CentOS 5 could handle the integrated network card (from `lspci`: Ethernet controller: Marvell Technology Group Ltd. 88E8056 PCI-E Gigabit Ethernet Controller (rev 12) ) because i already had installed exactly the same box with 5.0 . Of course i tried to setup 5.1 and it was not possible to use that integrated card anymore. Frustrating especially when i wanted to setup the box over the network, like i always do ...
From the 5.1 release notes, it was stated that the sky2 module was updated to a newer version (version 1.14) but i was not expecting that it removed hardware compatibility ! In fact, the sky2 module was backported by Red Hat into 5.1 but it was decided in the main kernel tree to not support anymore the Marvel 88E8056 chipset with the sky2 module .. at least that's what i understand from this mail sent by Linus himself (search for sky2) . The only way to get your network card directly is to setup CentOS 5.0 and not update the kernel with the one from 5.1 ... at least until I/we found and publish a workaround (like an updated module through kmod or something else ...)
That reminds me to always use good hardware and not playing with exotic or cheap hardware .. like for example the fakeraid controllers...