I am well aware that the documentation for the 780i SLI clearly states that 8gb of RAM is the maximum.  However, I have had motherboards before which had a specifically stated RAM maximum, and I was able to successfully install much more RAM, often without changing any BIOS settings.  This board was released when the largest DDR2 RAM sticks were only 2gb, hence the 8gb stated maximum may just reflect the four slots with 2gb sticks.

Has anyone here tried to slap 4x4gb chips in the MoBo for 16gb total? Or even 4x8gb for 32gb?

In other words, I am wondering if the 8gb maximum is a real limit which is built into the architecture, or merely an archaic assumed limit.
I assume someone here has tried this or knows for sure... I figured I might as well check here before I go out and buy some sticks for experimentation.

(and yes, I actually do have a use for over 8gb RAM - beyond mere curiosity.)

Yes, everyone I have asked assumes there is a chipset limitation to 8gb - but I am yet to find someone to confirm this with either a real trial or other evidence.

Yea, I'll probably just have to try myself.

On that note, are there any known DDR2 sticks at 4GB or 8GB which are at least known to work in an 8GB or less config?

I believe I have read about some folks getting 8GB total with two 4GB.  I figure it would be best to grab some sticks which I know work before I start experimenting with the 16GB+

I haven't seen a response back to the original question other than what I had found on the internet doing searches.  I run 4 sticks of 2GB ram without issue.  I run linked/synched at 800Mhz even though they are rated for 1066.  Everywhere that I've found on the internet that mention the 780i say 8GB is the limit.  It's not worth dropping the cash on DDR2 anyway.  You are better off going with the x58 and DDR3 at this point.