I have this board and am using it successfully as Hybrid.
DVD install, 7.10 RC 2, amd64
Asus M3N78-EMH HDMI
AMD Phenom 9850 BLACK EDITION 2.5GHz Socket AM2+ 125W Quad-Core Processor
4 GB DDR2 800Mhz RAM
I have also added:
NVidia 7200 PCIe Graphics Card
Intel 1000 PT PCI-X 1x NIC
I originally purchased this board for duty as Living Room MD. But had the reported NIC problem. It would initially PXE boot, but would fail with NIC problems. I purchased the Intel card, but have been unable to cause it to PXE boot. If anyone has any experience with Intel's Boot Agent, what's the trick to enabling PXE boot? I can not get it to show in the BIOS as an available boot option, nor do I get the PXE message during boot. I have tried the Intel Boot Agent software, and using the dos command with switches to enable PXE boot, to no avail.
However, I have made this board work well as Hybrid, with Intel NIC, in single NIC configuration. I have a Linux based firewall with DHCP server disabled. I have modified my dhcpd.conf, dhcpd.conf.tpl, and interface files to support my firewall as gateway. With my Linux firewall handling internet routing, and my LinuxMCE box doing DHCP. My clients route correctly to the internet, and my MD's and other workstations pull DHCP addresses and PXE boot correctly. I do prefer this, although it's outside the recommended setup. In my experience, LinuxMCE does a poor job on routing. My P2P clients, and many other download clients download at significantly lower speeds than with my firewall.
My system appears stable, although it's only been up for a day. Running UI2 + Masking.
I will post again as I work to resolve my couple issues...
1) NIC drivers... then I can PXE boot this box, and use it as just an MD as planned.
2) NVidia 8200 drivers for onboard video... from other posts, just an upgrade of the NVidia drivers should resolve this.