c1scy has been running slow (compared to c1scx, which does basically the exact same thing *) for many moons now. We've looked at it but never been able to identify a reason why it should run slower. I suspect there may be some bios setting that's problematic.
The RCG build process is totally convoluted, and really bad at reporting errors. In fact, you need to be careful because the errors it does print are frequently totally misleading. You have to look at the error logs for the full story. The rtcds utility is ultimately just executing the "standard" build instructions. The build directory is:
The build/error logs are:
I'll add a command to rtcds to view the last logs.
(*) the phrase "basically the exact same thing" is LIGO code for "empirically not at all the same"