I have a ECS P4M800PRO-M2(V2.0) and a Gigabyte GA-8VM800PMD-775-RH (rev. 1.0) mother board I plan on modding to support more cpus as they have AGP and Win 9x era drivers.

Both are using VIA P4M800 Pro Express Chipset which as far as I know supports up to Core 2 Duo E6700 at 1066FSB and possibly E6850 cpus at 1333 FSB on the highest end boards known to have these chips.

These 2 boards however lack support for those cpus as I've tried them both and it failed.

The ECS does officially support the E6420 cpu and currently has a E6320 cpu in it.
I probably just need to add support for the E6700 for it to work since it seems to be a similar 65W/1066FSB cpu to the E6420. If higher FSB can be set I'd use a E6850 at 1333FSB.

The Gigabyte on the other hand dosen't support ANY C2D era cpus and only goes up to 800 FSB though I'd only want a E4700 in that mobo max anyway as I have an unused one land it would fit perfectly in it if the bios can support it.
The cpu will also probably need to be pin modded from what I've read to support the older VRM on it.

I only plan to run these cpus at stock clocks so I won't worry about overclocking support, other than higher FSB to support more CPUs at stock speeds, as I doubt these mobos could handle any more than that.

If any of these can also be modded to support higher ram speeds too that'd be great as I mostly have 800mhz ddr2 so it's slown down considerably running at just 533 on these boards.

Also the chipset supports 4gb max but both only have 2 slots and my dual 2gb stick kits I have don't seem to enable more than 2gb in these mobos.
If anyone knows of any kits that will do 4gb on these boards, then let me know.

If anyone has any bios mod downloads or at least tips/guides I can follow so I can try to mod these myself let me know.