I use a little 3rd party program called WinAFC. You can do it in the Task Manager but Ryzom has to be reset each time. WinAFC uses a text file to assign specific processes to specific cores so you can run multiple clients each on a different core.
http://affinitychanger.sourceforge.net/
http://affinitychanger.sourceforge.net/
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Remembering Tyneetryk
Phaedreas Tears - 15 years old and first(*) of true neutral guilds in Atys.
(*) This statement is contested, but we are certainly the longest lasting.
<clowns | me & you | jokers>