My Acer C7 is running Chrubuntu. After I bought an 8GB ram extension, Minecraft is still running with only 5-9 fps. My system shows 9.4 Gigs of ram running, but this still makes no difference to Minecraft. I allocated more memory to Minecraft but this still didn’t make any changes to the lag. Why is this?
I suspect the combination of low-powered CPU and graphics is causing the framerate issue, rather than RAM.
Adding extra RAM would help in situations where the machine is running out of memory. If it isn't, extra RAM will make zero difference to in-game performance.
One test would be to run
top in a console while running Minecraft. If the CPU is hitting maximum (100% for single-core CPU, 200% for dual-core, etc), the CPU is probably causing (or contributing) to the low frame rate.
As far as I know the CPU in a C7 is going to be soldered onto the motherboard. Upgrade options are extremely limited (unless, as the commenters in that Tom's Hardware thread say, you're handy with a soldering iron).
Unfortunately, it's just not a gaming machine.