Dual channel with Intel 915 chipset

[Fox5]

I've heard that the 915 chipset has more laxed dual channel restrictions than previous chipsets. But how much more laxed are they?
Can you now buy any two random brand sticks and have them work in dual channel?
How about different sizes? Can you mix a 1GB stick and a 512MB stick? I've heard people say they get dual channel with this, though their memory speed downgrades, but they didn't specify if both DDR2 sticks were PC2-4200 or if one was PC2-3200.

 

[RBauer]

I have the 865 chipset and I can mix the DDR sticks as far as manufacture and cas ratting but must be the same size and speed. Not sure this helps any.

Honestly running DC i wouldnt want to mix sizes

 

[Fox5]

Well, I'd imagine if they're different speeds wouldn't they just downclock to match the slower one?