My current project is trying to utilize Flex as the UI on small form-factor touchscreen laptops/netbooks. Performance in this case is a must, especially since the application is kicking off extremely resource intensive applications in the background. So far, with a little tweaking we've been able to keep Flash in check as far as CPU and memory consumed, but I've run into problems when trying to implement any sort of coverflow display component.
It seems that all the coverflow components I can find either use Papervision, or are based off Ely Greenfield's tutorial... That wouldn't be a problem, except both seem to spike the heck out of the CPU when they are used.
In my app I'm loading up 15 items at a time, isn't using a repeater, gets children added just once, etc. Memory doesn't seem to be too bad, but on the (5 year old) Panasonic Toughbooks I'm developing for, CPU usage jumps from an acceptable 5-10% to 60%+ even when the application is idling. If usage spiked during the animations that would be fine, but once it goes up it never comes back down.
Does anyone know if there something inherent in the faux 3D that causes this, or are there solutions out there that can still do the coverflow look without the ridiculous overhead? Ely Greenfield's DisplayShelf component seems to be the best of the bunch, but minor digging hasn't enlightened me as to why even when sitting idle the app sucks up the majority of my CPU resources. (Note that I've done a lot testing and profiling on this, it is, without a doubt, the coverflow components I've tried that kill things.)
I'd be interested to hear if anyone knows of a high performance version, and I'm just curious as to whether any of you think it is possible to fix at all, or whether I should just throw out the coverflow concept in general since it won't ever mesh with my performance needs.
If your target CPU is a 5 year old, mobile CPU, then there's not much you can do.
On a modern CPU (dual core 2.5ghz), Greenfield's example is about 10% CPU usage. I'm actually impressed you're getting 60% on those old CPU's, that's pretty darn impressive IMO.