iXBT Labs posted a review on the AMD Phenom II X3 720 and X4 810 Processors. Here's an excerpt:

What concerns relative results, both Phenom II processors generally perform on a par. In games that can use three cores or less, the triple-core processor takes the lead owing to larger cache per each core. However, the 810 model shoots forward in the latest games that actively use four cores. That is, it looks more promising here. Core 2 Quad is lagging behind both competitors. In those games that can use four cores, our Phenom II with three cores still outperforms this processor. This fact agrees with the theory -- perhaps AMD introduced the monolithic design in its Phenoms too early, but it has apparent advantages over joined cores (only when intensive data exchange between cores is required). But codecs, rendering, and some other multi-threaded tasks barely loaded each core with its own thread, more complex options were out of the question. Now that Phenom II processors look better even in tasks that were not optimized for multiple cores, there appear applications that benefit from the monolithic multi-core design as well.

A few words about operating temperatures of the overclocked processors. Subjectively (judging by the speed of the cooler necessary to provide similar temperature of its fins -- barely warm), all three processors were identical in this parameter under load. In other words, there will be no problems with quiet and efficient cooling. Temperature of the cooler base was 32-40°C in all cases, depending on the load, with the air temperature of 26°C. Maximum temperature of both Phenom II processors under load did not exceed 55°C, Core 2 Quad -- 63°C. However, these data come from integrated sensors. On one hand, we have no grounds to distrust them. On the other hand, we cannot verify them.