are you running other programs? that could be taking up the rest of your memory. Open up your task manager go to processes, sort by CPU and it will show you what is taking up the memory. It could be another program you might think it closed but it is actually open.
Yes the CPU load is not as accurate as it is just monitoring the current CPU it is executed on. If you have 99% CPU load and 2 CPUs, it could as well be 50% load maximum only. I try to optimize this but it is no priority right now.
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