I'm slightly sad to see my old radeon 9600 card with Compiz being obsoleted. My motherboard in that machine shorted out somewhere and I was left with a bricked machine. Since the product was essentially about 5 years old, I decided to go ahead and buy new equipment. I'm now the proud owner of an Intel Core 2 Duo E6750 with an Intel DQ35MP Motherboard. I copied my old hard drive data to a new drive and am back up and running without a lot of headaches.
What better opportunity to explain how to get Gentoo working on this hardware.
First off, I found a couple good resources for this product and Gentoo already out there. I'm just adding my comments and aggregating things on one place in case someone else has this setup and would like to quickly get up and running. I'll add links to those and have you follow those directions where appropriate.
Booting from the Gentoo CD
It appears that the Gentoo kernel included on 2007.0 has an acpi bug that affects these mainboards. I was able to boot from the CD if I added "acpi=off" to the kernel parameters. Also, there is only one IDE port on the board. I had trouble getting the live CD to detect both IDE and SATA drives. I found somewhere a reference to adding all-generic-ide to the kernel parameters and this got me at least down the road far enough that I could see the drives and copy data. My IDE drives became something like /dev/hdi and /dev/hdj.
The Gentoo site for safe CFlags suggests using "-O2 -march=prescott -pipe" for the Core 2 Duo chips. I've changed my make.conf accordingly. I didn't feel like recompiling my entire system though. My old -march was set to athlon-xp. So far, I haven't had a single problem but I guess if you're worried you can always reemerge everything.
Compiling your new kernel
After you fetch some kernel sources, you need to determine whether they'll be suspect to the same ACPI bug that the Live CD suffered from. There is a Gentoo forum thread that walks through this and other problems. For me, gentoo-sources-2.6.23 needed patched. I think the 2.6.24 line of kernels may have already had this fixed. You can always try skipping the problem and then recompiling with a fix only if you need it. For me, the q35.pci.patch from the Gentoo Bug Report fixes my problem. You'll need ACPI to take advantage of the duel core chip by the way so don't ignore this.
The Gentoo Wiki, as always, has a good reference on the Q35 Chipset and setting up your system. I'd follow that guide for configuring your kernel. I don't think I had any problems that weren't covered by that guide.
The guide above has all the right configuration settings to get Xorg running with AIGLX. For me, Compiz works just fine. It is definitely slower than a dedicated card, but since my machine is a work machine, I'm not too worried about my frame rate.
I want to point out that some of the Xorg settings that I had trouble with though.
- Xorg 2D drivers
The DQ35MP has an Intel GMA 3100 Integrated Graphics Card. You need the "intel" driver to run Xorg. This driver is obtained by emerging xf86-video-i810. If you have VIDEO_CARDS="i810" in your make.conf and you re-emerge xorg-server, you should get this but you can emerge it directly if there is a problem.
- Xorg 3D drivers
Searching around, or viewing the forums, you might find references to using x11-drm to get the i810 and i915 kernel modules. I tried those but they were incompatible with my kernel and didn't load. The gentoo-wiki guide correctly suggests to use those kernel modules directly from the kernel sources. Depending on your kernel, YMMV.
Check the guide again for configuring X. I have Compiz up and running just fine and using Direct Rendering. Again, it isn't a speed demon but it works! Good Luck.