Go with the athlon tri core, its been proven by thw that the 4th core doesnt add much performance to games and neither does l3 cache... 5%~ at most i think from memory. Also if you get the tri core, maybe youll get lucky and you can unlock the 4th core and l3 cache
i've been looking at those three myself with a close eye on the x3 435 to replace my 7750, that price looks so nice. I don't think you'd go wrong with any of them, but for the rest of us maybe you can do a follow up with whatever one you choose?
If using it mainly for gaming I'd go with a Phenom II with the L3 cache instead of the Athlons ( the L3 is useful for gaming systems) - but the problem with the X3 720 you linked is it is OEM and therefore does not have a warranty like the others (OEM parts only carry the vendors warranty and Newegg does not offer one with it !!) - or a HEatsink\Fan (which you probably would want to replace anyway !)- I'd look for a boxed version of the 720 or get the X2 555 if on a tight budget.
I have an athlon IIx4 620 at 3.25GHz. I like having the extra core but it's not necessary. Dragon age seems to be using all 4 cores but 1 is at 20-50% while the rest go between 60-100%. That was during loading. After the level loaded 1 is at about 80-100% and the rest are at 40-60%
based on the stats from anandtech, I see no gaming difference between the 435 & 630. The biggest advantage the 4th core seems to currently offer is in video encoding which I don't do.
I like the Phenom II X3 720 but if I would rather wait for the Phenom II X4 to come down in price.
Plus with Tom's review of the 435 I think its the CPU to go with. With the extra $30 saved I got Rosewill CPU cooler so I can OC it and make up any small difference compared to the 720. Then in 12-18 months I can upgrade again.
"Here's where it all comes together. Look at the Athlon II X3 435 versus the Phenom II X3 720. For three-quarters of the price, the Athlon II X3 435 offers identical encoding ability, less than a three percent disadvantage in gaming, and less than a five percent disadvantage in productivity metrics." http://www.tomshardware.com/reviews/athlon-ii-x3,2452.h...
So I got the 435 today. Stuck it in my PC, went into ACC to set it to All Cores. Ran my CPU-Z and it states.........Phenom x4
I jump for joy, then I run firefox...it locks up. I launch IE, that locks up too. I go into ACC and set it to Auto, run CPU-Z again...it states Athlon II x 435
Oh well. The good news, with the money saved I got a Rosewill cooler. I used the stock thermal grease on the cooler (even though I have Antec's silver compound). Set the fan to the lowest setting and my CPU is idling at 27c, never reaches 40c during gaming.
So I OC the CPU to 3.3ghz. It now idles at 31c and tops out at 50c after an hour gaming. Not bad for $67 CPU and $12 cooler (newegg gave me a 10% discount!)