The PC GAMESS/Firefly hints (somewhat outdated) . ... This will help you to select the optimal settings for your particular PC GAMESS/Firefly job. ... Generally, consider any direct method as being only the last resort in the case of the disk space limitations. ... Memory. Generally, it is not recommended to allow the PC GAMESS/Firefly job to use more memory than the amount of physical memory available on your system (though, there are some exceptions also). ... Job specific. MP2 . ...