Outfile interference
Hello, is it OK to run several oclHashcat instances that have the same in/out file, or are they going to interfere or cause a bottleneck?

infile (dictionary) is ok, but outfile can create problems. i would not recommend it.
i have never had problems with multiple instances writing to the same outfile. However using the same infile with --remove will cause problems.
Truth is it depends.
If you're having a lot found, you will definitely ruin your files.
If nothing is being found, no problems at all.