Hex core efficiency in Bridge CS5 and Camera Raw 6.0

Question

Conclusion: Batch processing of files in Bridge CS5/Camera Raw 6.0 is limited by an unknown factor which I currently believe to be software design and/or software implementation.  While performance on a dual core would be more or less CPU bound, and on a quad core would use the bulk of the available CPU power most of the time, on a hex core machine the CPU is woefully underutilized; i.e. I could be doing the same work in substantially less time.
Suggestion: At the very minimum, allow the option to have Bridge/Camera Raw process N (where we choose N, given that a dual socket motherboard will be able to have 24 cores in the very near future) files simultaneously, so we can tune our own systems for the disk IO vs CPU bottlenecks we each have.  At best, automatically keep the CPU(s) running all cores at or near peak all the time, or until you run out of disk IO bandwidth.
Observations taken with the Windows 7 Resource Monitor and the SirReal G15 keyboard applet
Camera Raw Batch actions:
  When I select a number of photographs (I typically select scores to hundreds), either fresh RAW files from a Canon 50D or existing DNG's converted with prior versions of Photoshop, and apply some change to all of them (for instance: changing from the 2003 Process with ACR 4.6 camera profile to the 2010 Process with the Camera Neutral camera profile, I see very tiny sections of disk IO (not exceeding 20MB/s on a high end SSD), no hard faults/s in memory, no real network IO, and CPU follows a very distinct pattern, with about .75 to 2 seconds at each of the following CPU levels, in sequence:
18 (one core plus a bit)
70-88 (5ish cores)
18-23% (one core plus a bit)
45-55% (about 3 cores)
repeat
A very important feature for me, Bridge CS5 Preview Extractions on a new folder show 33-45MB/s of disk activity, and a solid, exact 25% (1.5 cores) of CPU with dips to 19% or so.  This very clearly indicates that the Preview Extraction feature isn't able to use most of the cores in my processor.
Build: a new build computer (Gigabyte GA-890GPA-UD3H rev1.0, BIOS F6) with an AMD Thuban 1090T 3.2Ghz hex core (running 5% above clock, FSB change to 210Mhz from the 200Mhz default, Prime95 stable for days), with 8GB of DDR3 RAM, and all Bridge, Camera Raw, and Photoshop cache and files running on an OCZ Vertex Turbo SSD.  OS is Windows 7 64-bit.  OS level page file is completely disabled.

Answer 1

Is it possible you're overwhelming the main memory bandwidth by the fact that you are working on (multiple) large images?  Multi-core machines can only work on as much data as they can get from/to memory, and what you're doing is kind of flushing data right through the cache.  I'm less familiar with the AMD architecture, but doesn't the concept of 6 cores on one chip mean that they ALL share one main memory buss?  This could be a case where given the task, more cores is not better.
It may also very well be that the entirety of Photoshop, which is at its core a relatively old application (architecture-wise), is not programmed to use multi-threading as well as it might be.  Getting multi-threading to work right in an application is no picnic.  And don't forget, this software is crafted to build and work in two widely different environments (Mac and PC) and so may not be able to use all the fanciest features of any one of those two realms.
-Noel