Fantasy Garden Animated Wallpaper is a single file, using the registry to store language. run at Windows start if you prefer etc. It depends on your system's graphics hardware supplying the functions it uses -- not on that hardware's raw horsepower. A quick example, it won't run in my XP Mode VM running in Microsoft's VPC host -- it will run in my win7 32 bit VM running in the V/Box host, because V/Box has some emulated D3D graphics support. Both VMs have the same amount of allocated CPU & RAM.
#1: <i>"DOSE put a fair amount of stress on the video card causing the cooling fan to run much more than it normally does,"</i>
#2: <i>"These things are energy wasters."</i>
DesktopPaints sells software to add animating effects to your still image -- Animated Wallpaper Maker [it's on GOTD from time to time] -- & they sell animated wallpapers that they've made. They do require certain capabilities from your PC's/Laptop's graphics hardware in order to run, so some systems might be totally out of luck -- the 1st time I saw their Wallpaper Maker on GOTD I spent an afternoon creating wallpapers for people it turned out couldn't run them at all.
They do not use a lot of resources from my graphics card [AMD/ATI 7870] -- at most a couple or few percent -- but as Alan wrote about his laptop, mileage will vary. I'd guess that on some hardware it'll use enough CPU to show up in Task Mgr. as well -- some graphics stuff can be handled by the CPU [at lower speed] when the graphics hardware isn't capable, & some systems have their graphics built into the CPU. The important thing to remember is that *mileage varies* depending on your hardware -- don't ignore this GOTD *Just* because of Alan's experience, but at the same time realize that the same *might* happen to you. With the low impact of a single file making it work it doesn't hurt too much to try.
The amount of electricity your PC/laptop or tablet uses depends both on the hardware & how hard it's working. I don't see any additional voltage used when I run their animated wallpapers -- both the graphics card & CPU stay in a lower power state. It just uses what's already there in that minimal state. OTOH my graphics card requires more power just to run, especially compared to if I just used the GPU built into my CPU. That graphics card also requires a higher output power supply, that wastes more electricity than a lower output version, & it requires more cooling capacity, which also uses more electricity.
So, for me running animated wallpaper has really very minimal costs, if any, but I'm already wasting some. Lower powered systems, particularly something like a laptop, might see increased use of electricity. That said, more philosophically, why have it if you're afraid of using it? Read books instead of e-books &/or watching movies. Use pen or pencil with paper rather than running software. The big reason I don't regularly run animated wallpaper is that normally I can't see my desktop anyway -- if I'm at my PC I have a bunch of Windows covering it. :)