Limiting ram use due to disconnected channels

I have a Gateway nv5929u which comes with 4 gigabytes of ram. In preparation for a planned upgrade later this year, I bought 16 gigabytes of ram so that when I upgrade I can just swap the ram from my old computer to the new one.

I did this, however, with the understanding that my laptop does not support more than 4 gigabytes per ram stick; a review on Newegg said that someone was successfully using oversized ram sticks in their laptop, presumably on Windows. Apparently the channels for any additional ram are simply not attached.

When I installed the ram, my computer booted up perfectly and ran very fast, befitting the increase in clock speed and reduced latency. However, it thought that there were 16 gigabytes present, and when I ran some memory-heavy processes, it kernel panicked and crashed.

Would I be able to limit my memory usage to within what is physically hooked up?

On a side note, none of the GRUB boot options other than the first work at all, so I can't test Windows or run memtest86. They just induce rebooting. Is this related?