Are laggy adjustments/rendering camera specific?

Question

The thread on thumbnails got me to thinking, some people report snappy adjustments, quick rendering and great performance with A3. Others (like myself) experience slowdowns on some photos after applying several layers of edits to a photo ("processing" thumbnails, slow rendering of adjustment changes etc.)
Just a few things that tend to take a long time to render an updated screen view for me (i.e. I get a low quality jaggy preview and it takes up to 20 seconds to "sharpen up" and show the changes:
. ANY changes to the Raw Fine Tuning brick, especially in 100% view
. some brushes take a long time to render changes (skin soften and sharpening to name a couple) again, worse in 100% view
. noise reduction (worse in 100%)
. Edge Sharpening (worse in 100%)
. rendering a proper image after zooming 100% into a photo after it's been adjusted moderately with the above adjustments, or cropped/straightened. Also slow to render if scrolling around in 100% view.
Notice that the worst wait times tend to appear in 100% view, though zoomed out sometimes I still get the "loading" pinwheel. These are adjustments that I prefer (justifiably so) to do in 100% view but the lag is just terrible sometimes. Some photos are worse than others, and it tends to be worse as the adjustments pile up.
My equipment is listed in the sig, my MBPro tends to be a bit faster than the iMac. Before you ask, I've done all the standard performance enhancing things (previews settings, faces off, defrag etc etc etc).
I am using Canon 7D full size raw files (18mp, ~25MB files). A couple people in the other thread mentioned this sort of lackluster performance with their 7D files, and I've seen people with 5DMk2's complain as well. I wonder if Aperture has a hard time dealing with large raw files, specifically Canon raw files.
So informal poll, three part question:
(1) Are you experiencing slow downs in rendering of adjustments on your photos, especially at 100% view?
(2) What type of file from what camera are you using (i.e. large .jpg from Nikon D70, full size raw from Canon 1dMk4 etc)
(3) What is your computer set up?
I wonder if this is a trend, and am just curious to see if my wild theory has any merit.
I see no reason why my two machines run LR and PShop flawlessly and with instant graphical feedback of ALL adjustments, while A3 lags and chews on the adjustment for up to half a minute before showing me what my sharpening move did to the photo at 100%.
If it is some sort of trend, maybe it's fixable in a software update that might be forthcoming. I really, REALLY like Aperture 3, it's pretty much exactly what I want/need for a photo management/editing program (save for the lack of output sharpening, but that's another thread for another day :)) I just wish it was as snappy as the Adobe products with my 7D files.

Answer 1

I certainly think that the size of the file is a factor . My 5d MKII files (>20Mbyte) are slower than files from my S90 (around 10MByte ), but on my system configuration perfectly manageable and usable.
I think the file size, GPU memory/speed and memory in general are all factors that interact together to create what some see as lags and slow downs.
Sharpening and noise reduction is a fairly intensive algorithm to apply in real time ( I know, I have written code to do it in non real time and it's a lot of pixel sampling and comparing, computing ).
I have conducted extensive testing with Aperture 3.0 and for that matter Lightroom as well ( lot's of people point to LR as being much better and I'm fed up with the generalization ). The reality is, both programs struggle to keep up with the application of real time application of localized brush strokes with large files, especially when you have lots of adjustments applied. I have some interesting data comparing these things and might publish it one of these days.
I think Apple need to be realistic with minimum system requirements to run fully all of the features with programs like AP3. Sure, you can apply adjustments to a small JPEG when you only have 1GB of RAM of 128MB GPU RAM etc, but it's common sense that at some point when you files are 20, 50, 100MB you are going have an issue when you are attempting to overlay in real time multiple computations to an image.
I also think Apple has not yet optimized the code in this area. I have carefully monitored the number of processor threads, memory usage and CPU cycles when some of these things are being applied and, while I am not privy at all to anything under the hood with Aperture, as a fairly seasoned software developer of real time automation software, I think they have some tweaking to do, that will make this better for more people across a range of hardware and image sizes. At least I hope so! It will be interesting to see what the next update brings.
AP3 is really a very, very powerful tool and I liken it to the first and early releases of Final Cut in the video world. I remember lots and lots people complaining about performance with Final Cut - mostly it was the system setup, limited resources in the machine and not yet knowing the best work flow. I see the same trend on some of these threads with AP3.
No doubt in my mind Apple could have done a much better job of quality control here and I fear they bowed to pressures to release something early. For some the out of the box experience has been good for others not so much. I have no doubt they will get it right, but it doesn't help people having issues at the moment.
Just my 2-cents.