Unlocking the 4th core of the phenom II X3 720

Im upgrading my system after my failed attempt at overclocking my amd 7750. my current processor has suffered permanent heat damage and now my entire system is slow. i read in some reviews for this motherboard

i am quoting Jon:

"Pros: Everything working as it should. Easily opened 4th core on AM3 720 with no issues so far.
Only other thing changed in BIOS was memory speed to give me 1066.
Running stock/retail 720 fan.
Newegg's amazing fast shipping. Ordered Wed night & was at my door Friday afternoon!

Cons: None so far.

Other Thoughts: Got this board a couple weeks ago and everything is working great so far.
Easy enough setup.
Comes with user manual but doesn't cover many BIOS options, went to their website & downloaded BIOS user manual though."

there are plenty of people saying this, will unlocking the 4th core drop the opeating frequency of all the the cores to equal 2.8 Ghz? also how much will this increase the preformance.

the other motherboard im looking at is this one this MB supports my current DDR2 1066 MHz Memory and also supports DDR3 1333 Memory, there is only one review for this product and it isnt very helpful, will this motherboard be able to unlock the 4th core in the amd phenom II X3 720

would this CPU be a better choice and will it be compatable?

actually no not all of them are supported, i know for a fact that the AMD Phenom II X4 955 is not supported and it is a am3 cpu