The 16e WUs require up to 1GB RAM. If your system doesn't have enough physical memory, it will use virtual memory (paging memory in and out of RAM and onto disk) which is horribly slow. If you don't have enough RAM, run the 15e and 14e WUs. They only require up to .5GB RAM. If you want more credit, run 15e as they pay better than the 14e. If you want badges, run both.