Conclusion: What $99 gets you
Back in June, we reviewed the Athlon II X2 250 and found that the $15 price difference compared to the higher end Phenom II X2 550 was simply too small to justify the savings -- even though it delivered superior performance than its Intel competition which came from the Pentium E5400.
Today, we do not have an entirely dissimilar situation. The Athlon II X4 620 is just $20 cheaper than the Phenom II X3 720; and while it has the advantage of shipping with all four cores enabled, it also lacks the massive 6MB L3 cache of the Phenom II X3 720. Thus in terms of performance the triple-core chip will likely be faster than the Athlon II X4 620 in most cases, as it is also clocked 200MHz higher.
That said, there is no disputing that the Athlon II X4 620 is now the world's cheapest quad-core processor -- and it has more than enough grunt to match the Intel Core 2 Quad Q6600.
The cheapest quad-core processor that Intel currently has on offer is the Core 2 Quad Q8200. Priced at $150, it is considerably more expensive than the Athlon II X4 620. Although we did not include it in our benchmarks, the Q8200 can be considered slower than the Q6600 as it is clocked 70MHz lower and features half as much L2 cache. This plays out favorably for AMD's budget quad-core part, as the Athlon II X4 620 had no problem beating the Q6600 in the majority of our tests.
The Athlon II X4 620 and Phenom II X2 550 make up for another interesting comparison. Both processors cost $100 despite being quite different, but overclockers are likely better off with the quad-core Athlon II X4 620, as it will deliver more performance on a clock for clock basis.
On that topic we should note that the Athlon II X4 620 did not overclock as well as the Phenom II X2 550 or Athlon II X2 250, both of which reached 3.90GHz on our test bed. It seemed that the Athlon II X4 620 was limited by its low 13x clock multiplier and the fact that going above a FSB of 285MHz caused the system to come unstuck. Still, a 42% overclock from 2.60GHz to 3.70GHz is nothing to be ashamed of, and this kind of flexibility will help Athlon II X4 620 owners squeeze a lot more performance out of their system.
Overall we are impressed with the level of value that the new Athlon II X4 620 presents budget builders with. Priced at just $100 makes it possible to pick up this quad-core processor, along with an AM2+ motherboard and 4GB of DDR2 memory, for roughly $200 -- which I don't need to tell you is a steal. AMD may not be doing terribly well higher up the scale, but for now they are delivering some very capable processors at truly competitive prices.