Full-screen (spacebar) preview quality testing

Question

[For background story, please read http://forums.adobe.com/thread/1056763 but be warned, it's very l-o-n-g!]
In brief: some people have noted that Bridge full-screen (spacebar) previews (FSPs) don't accurately reflect the sharpness of a photograph. Sometimes this can be explained by individual configuration problems, but it's clear that this is a common issue amongst people using Bridge to assess/score photograph sharpness, without having to build/examine 100% previews for every image.
[It's worth noting that one common reason why FSPs aren't very sharp is because the Bridge advanced preference "Generate Monitor-Size Previews" hasn't been ticked, as this produces a higher resolution image cache.  Another cause of very fuzzy previews is random and unexplained, but can usually be solved by restarting Bridge and/or clearing the cache for the selection.]
This discussion concerns the lack of sharpness seen only in FSPs.  It can be described as "a subtle but significant loss of detail and sharpness, similar to a slightly out of focus photograph"; imagine a photo with a little bit of blur filter, or a Photoshop PSD at a non-standard zoom setting.  This "softening" of the image is caused by Bridge asking the graphics processor to resize the image cache to fit the display.  If you select the Bridge advanced preference "Use Software Rendering", you can improve a poor FSP slightly, at the expense of speed, by bypassing the graphics processor.
The test
Visit this web page and download the last image ("2362x3543 pixel, 4.5 Mb") to your computer.
Browse to this image in Bridge, and view it full-screen by pressing Spacebar.  Take a screen capture, and save it as a TIFF or PSD.
Adjust your slideshow settings (Ctrl/Cmd-Shift-L), picking "Scaled to Fill", then click on "Play".  Save the screen capture, as above.
You now have two screen captures: one FSP, and one cache JPEG reference shot.  Examine them side by side at 100%, or layer them in Photoshop and use the hide layer button to flick between images.  Pay particular attention to the two left-hand photos, the sharpness check text, and the converging lines.
Make a note of your computer's operating system, graphics processor and driver version, as well as your largest display's pixel dimensions.
Post this information below, together with high quality (10) JPEGs of both screen captures, labelled FSP and REF, and any observations, so we can all see.

Answer 1

OK, it usually takes me a while to let the penny drop, especially when it comes to maths...
I also am busy with the transition of my new Mac pro but with al this here are my results. I include several screenshots but due to upload limit of 2 MB per image in here I downsized the original screenshots a lot, but hopefully it will be clear.
For full screen screenshots I have the asked FSP and REF but also the 100% preview in Bridge with space bar and click. Don't know what your file size is but using EOS 1Dx with 18 MP CR2 files (converted to DNG) it does take me about 1,5 - 2 seconds for both loupe and FSP to build a 100 % preview, and I seem to recall this was not very different behavior on my previous (6 year old) Mac Pro.
You are right (of course... :-) ) regarding the difference between FSP and REF, when studying closely there is a significant detail difference between the FSP and the REF. However, only the 100 % preview matches the original jpeg. The FSP file is on closer look not so good with details but the REF file is only slightly better, both are not correct and therefor the 100 % is still needed.
Here is the FSP screenshot:
and here the REF screenshot:
also the 100 % preview in full screen screenshot:
and finally a composed file with details from original, 100 % REF and FSP:
As said before, at first sight I can't spot significant difference between all options and the full screen (as the preview panel HQ preview) let's me spot the vast majority of unsharpness issues, hence my multiple rounds of sorting and incases of doubt the 100 % option.
So while your theory is correct I'm afraid I  (still) doubt the usefulness of this all. If neither the FSP and the REF (although the latter does show a bit better result) can match the results of the original but the 100 % does it well I don't see an easy solution for improvement.
I agree with the quality from the screenshots Curt provided, but Curt also uses the embedded thumbnail instead of HQ preview option. Depending on his needs and hard ware availability it would be nice to see new results with the HQ and monitor sized previews options enabled.
regards
Omke