What is the difference between green and Chinese motherboards? Do colored ones really have less gold content? Is this just a myth that is perpetuated by refiners to pay you less for your material?

As some of you may know I started an electronics recycling division within my company to diversify and try to make up some of the margin that we were losing on steel when a half dozen yards decided to put in a shredder and royally screw up the profit margins in this area.

So now we have a couple of truckloads of scrap and after shopping it around I decided to go with a company that pays the same for "colored" and "green" motherboards. Some of their prices on other commodities are a bit lower, but I figured I can make that up in motherboards.

Do your e-scrap buyers pay the same for all motherboards? Or is this just a scam like "light copper" (most yards in my area are able to ship it as #2)?