Recently some pretty major advances have come around in the world of GPU based hash cracking. Up untill now there was not much for Linux which would utilize multi GPUs to crack password hashs. This has been changed with the release of Oclhashcat. The release of oclhashcat signifies a signifigant jump in the speed on linux based GPU systems. There is also a cpu based version called hashcat but for this article I will be reviewing oclhashcat
One of the nice things about Opencl is that it works on Nvidia and ATI based systems. As I do not have any ATI cards I will be focusing on Nvidia based systems. The steps for ATI would be the same you would just have to install the stream drivers rather than the Nvidia drivers. In order for opencl to work you are going to need the newest nvidia drivers.