Two hackers have managed to install Siri also on iPod touch. As you know some hackers already done for iPhone 4 and iPad 2. But the functions for the Siri are limited by the lack of recognition of the Apple servers.

Like on the iPhone 4 and iPad 2 execution speed is lower than the Siri on iPhone 4S. We can say that this is not the hardware issue because iPad 2 using same hardware as the iPhone 4S like dual core processor A5. According to the developer Steven Troughton Smith to accelerate Siri Apple uses ad hoc code and drivers and that drivers are not present in versions of iOS for iPhone 4 and iPad 2.

Of course Apple introduced Siri as top functionality, one more reason to buy the new smartphone because it has built-in hardware beyond the Update. However the Siri could be an attractive feature if Apple launch its for iPhone 4 and iPad 2. Many are hoping that Apple revise the plans and decides to make available the Siri also on the previous generation devices.