This information may be old, but I thought the eleven smooth client still uses the ECM 5 code. Not sure here at all, and it's possible it's been updated.

The best thing to do is use prime95 for stage1 and download the latest version of ecm6 for stage2. Perhaps I'm just out of touch with ecm lately.

This thread has the command lines to use prime95 for stage1. And mystwalker has given us a few different lines for ecm6 depending upon your computer memory.