How do I disable Hyperthreading in 10.6.7 on my 2011 MacBook pro 2.2ghz quad?

Question

I'm rendering a scene using Maya 2011, and it's only using two of the four cores in the batch render. I've read that Maya doesn't play well with Intel's Hyperthreading, so I want to turn it off while rendering. There isn't any processor preference pane, so I don't know how to do that. I've read it can be reinstalled from Xcode, so I downloaded it, but I've searched it up and down and can't find anything about processor or CPU preferences.

Answer 1

You better know what your doing
Lets see far as I can tell installing Xcode installs CHUD tools which you can set via the command line hwprefs
If you got Xcode 4 installed, do a 'man hwprefs' and see if it pulls up the manual.
If so the command is
hwprefs -v cpu_ht=false
hwprefs -v cpu_ht=true
(last one turns it back on)
HWPREFS(1)                               BSD General Commands Manual                              HWPREFS(1)
NAME
     hwprefs -- inspect and control low-level system and processor parameters
SYNOPSIS
     hwprefs [-v] [-h] [cpu_count={1..N}] [cpu_enable {1..N}] [cpu_disable {1..N}] [cpu_l2_cache={true,
             false}] [cpu_l3_cache={true, false}] [cpu_nap={true, false}] [cpu_hwprefetch={0, 4, 8}]
             [cpu_nop_dsts={true, false}] [memctl_readbypass={true, false}] [os_class] [os_type]
             [machine_type] [memory_size] [cpu_type] [cpu_freq] [cpu_bus_freq] [memctl_type] [ioctl_type"]
DESCRIPTION
     hwprefs inspects and controls low-level system and processor parameters
     -v       verbose mode
     -h       display help message
     cpu_count={1..N}
              number of processors available for use by MacOS X
     cpu_enable {1..N}
              enable a specific processor
     cpu_disable {1..N}
              disable a specific processor
     cpu_nap={true, false}
              processor nap
     cpu_l2_cache={true, false}
              processor L2 cache
     cpu_l3_cache={true, false}
              processor L3 cache
     cpu_hwprefetch={0, 4, 8}
              prefetch engines used by hardware prefetcher (PPC970 only):
              0 - all prefetch engines disabled, DST instructions treated as NOPs
              4 - four automatic hardware prefetch engines, four used by DST instructions
              8 - eight automatic hardware prefetch engines, DST instructions treated as NOPs
     cpu_nop_dsts={true, false}
              treat DST instructions as nops
     memctl_readbypass={true, false}
              memory controller (U3 only) read-bypass optimization (allows read commands to memory to bypass
              straight to read memory request queue, saving a significant number of cycles)
     os_class
              displays OS class {Cheetah, Puma, Jaguar, Smeagol, Panther, Tiger}
     os_type  displays operating system type
     machine_type
              displays machine type
     memory_size
              displays system memory
     cpu_type
              displays processor type and version
     cpu_freq
              displays processor clock frequency
     cpu_bus_freq
              displays processor bus frequency
     memctl_type
              displays memory controller type
     ioctl_type
              displays io controller type