Possible Low/Mid-Range Gaming?

I have been looking into some ideas to make a couple simple gaming machines (Android) so I can learn a little more about some different types of hardware and honestly a bit of simple curiosity.

I found recently found a few seemingly cool gadgets I am thinking about buying to test out and see how far they can be pushed.

the weakest of the bunch are Raspberry Pi and the newer APC - just simple Android computers that I was wondering how they could be upgraded/expanded upon. I know the APC is the better of these two but even so, it only uses an 800MHz ARM11 Processor and only 512MB RAM.
(http://liliputing.com/2012/05/via-apc-a-49-android-comp...)

The other things I was curious about were the Zero Devices Z-802 and the Z-900. Both of which are thumb drive sized Android computers. The Z-802 using a 1.5GHz Cortex A8 Processor and the other using a Telechips 1.0GHz Processor, both utilizing 512MB RAM/4GB Flash.

I can't find any benchmarking or testing to see how well they would do with games. I mainly want to know if they would be able to hold up to emulation and Android HD Games Like Modern Combat 3, N.O.V.A., etc.

Please, if anyone has any input/suggestions, it would be greatly appreciated. I just want to have a bit of information before I actually purchase the devices and start to work with them. Thanks!