You can set the following preferences in the 
		XGen category of the 
		Preferences window. 
	 
To return to the default factory settings, choose 
		 in this window. Note that this resets the preferences in every category in the Preferences window. 
	 
 
		  Cache Options 
 
		 
		- Memory Cache Size 
			 
- Specifies the maximum amount of system memory used when XPD caches and 
				Ptex 
				files are written to disk. 
				See 
				  Manage XGen files and directories. 
				 
 
		  Viewport 2.0 
 
		 
		- Draw method 
			 
- Sets which renderer to use when drawing primitives. When set to 
				Hardware Instance, Maya uses the Viewport 2.0 render. When set to 
				Legacy, Maya uses the XGen software renderer. Use Legacy to improve performance when instancing large numbers of high-resolution archive objects. 
			 
 
		  Threading 
 
		 
		-  
				Multithreading 
			 
- Turn on threading to improve the performance of primitive generation, modifier processing and patch evaluation.