I am seeing a number of smartphones with octo-core processors, but they often have lower processor speeds. For instance, I will see a quad-core with a 2.3 GHz processor and then see an octo-core 1.3 GHz processor. Adobe does not specify for Lightroom Mobile android anything concerning what processor speed or anything at all about a device with 8 cores.
Note: this assumes everything else being somewhat equal. I know that processor speed is one variable among many that can be a bottle neck. I wouldn’t expect a 2.3 GHz quad-core processor to work very well with 768 Mb of memory <evil grin>.