Penalty of using unsupported ServerWorks GC-SL chipset?

[Vasenin Alexander aka BlackSir]

What penalty of using Tyan motherboard on unsupported ServerWorks chipset GC-SL? I found a message in freebsd-questions: Benjamin
Thelen wrote that he tried using GC-SL and unable to use DMA on ATA. It's not my case - on MB I intrested there is a Promise 20270
RAID controller onboard, that supported (I asked Soren Schmidt). I apologise that there can be problems with USB,PCI or some other
things. Damn, HP, Fujitsu-Siemens and some local companies using only GC-SL for low-cost 1U server solutions :-(
	Vasenin Alexander aka BlackSir