You can limit the memory and the number of threads that Analysis Services uses by changing configuration settings. The easiest way to do that is by right-clicking on the server node in Object Explorer in management Studio, and selecting "Properties".
The properties are documented at http://msdn.microsoft.com/en-us/library/ms174556(v=sql.105).aspx.
For your purposes, memory and thread pool properties are probably where you want to change settings, depending what is your bottleneck.
You can reduce the parallelism of processing as well in the processing request changing server settings, using (or not using) the Parallel
element, possibly including the MaxParallel
attribute. To see the XMLA for the different settings, you can just right click on the object that you want to process in Management Studio and select "Process". Then click "Change Settings", change the settings as required, and click OK. Do not click on OK in the main dialog, but on "Script" in the top toolbar, and have a look at the generated XMLA.