Regkey: "Available ram on boot"
 

You can find it at HKCU Performance.

What exactly does this key do, is it a read out of the ram available or does it actually control it?

I don't want to try to change it with out advice.

Re: Regkey: "Available ram on boot"
 

I changed it, but the change did not survive a soft reset.

My understanding of this key is that it is written into right after the device starts, it's just reporting how much RAM is available. It doesn't actually change it, it's a read-only value basically.

I wrote in about this a while ago. It turned out to just report how much RAM was available when you booted the device. It doesn't actually affect anything.