It looks like Russians are using the same T72 model.
No, these are T-72B model 1985 and 1989, the Georgians are using heavily modernized T-72AV.
What is a Georgian military capacity to resist Russian army?
On the hostile ground? Next to zero I would say. And the will to do so - likely even less than that. Besides, currently just one Russian MRD is committed, but Russia can pretty much pour entire Caucasian military district there. Plus the Black Sea fleet. Plus the strategic aviation. Every branch will just love to try their new toys. No, whatever hopes the Georgian regime entertained they were gone the moment Russia did decide to cross the border.
From what I see, the plan was to do a lightning strike and occupy Tskhinval and then negotiate from a position of strength, leveraging on the "it's the Olympics, make peace!" bullshite. Given this is basically the only town of South Ossetia, the separatist state would have been decapitated. The real question is, how could the Georgian leadership behave in such a reckless fashion? Did the influx of money, equipment and US military assistance cause them to lose the grip with reality? Or was Saakashvili's bonapartistic regime really that desperate? In fact, the part of the US in all this is of much interest to me. Placing the blame squarely on South Ossetia at the very same time the Georgian tanks were assaulting Tskhinval is a sign of either extreme lack of information or extreme hypocrisy.