I did this and it's now running at a speed of 1.21 Mkey/s, it should be finished in 3150 years... I noticed that it's mostly taking all of my CPU memory though, so it's not working with my gpu's?
If you have a Nvidia card, use the oclvanitygen.exe file inside the same folder, instead of the vanitygen.exe
I have 3x R9 290. Which should I use instead?