Putting it all together
We've created a synthetic "overall performance per dollar" scatter plot to sum up our results. We're presenting our performance numbers as percentages based on an average of each CPU's score across all 18 of our performance tests. The 100% score corresponds to the slowest chip in our test lineup, the Athlon X2 5600+, and other scores are relative to it. As with all aggregate scores, we don't recommend you draw hasty conclusions from the results. If there's one thing we can say for sure after looking at all the data, it's that the performance picture can vary tremendously from one application to another.

As we've seen all along, AMD's processors bunch up tightly in the space under $250, making our task of sorting out relative value rather difficult. Unhappily for AMD, the Intel processors that occupy the same price range tend to sit further toward the left and top of the plot, indicating stronger performance per dollar. In fact, a range of Intel processors forms a nice line of values extending from the Core 2 Duo E7200 through the E8400, Q6600, Q9300, and Q9450. As we step up the ladder in price among these choices, performance increases by solid margins, as well.

In response to reader feedback, we've taken another look at overall performance per dollar that factors in total system costs. Below, we've modified the price figures on the X axis to factor in the cost of a complete system's worth of components. For our theoretical AMD systems, we selected an MSI K9A2 Platinum motherboard ($149.99), 2GB of Kingston DDR2-800 memory ($43.99), a 320GB Western Digital Caviar SE16 hard drive ($69.99), and an XFX GeForce 8800 GT graphics card ($189.99). Our Intel estimates are the same, except that we selected an identically priced Gigabyte GA-EP35-DS3P motherboard instead of the MSI board. Similarly, for our dual QX9775 system, we factored in the price of Intel's Skulltrail motherboard ($609.99) and a couple gigs worth of DDR2-667 FB-DIMMs ($149.99).

Taking the cost of other components into account helps us put the impact of CPU prices into context. After all, if you choose to spend $300 instead of $150 on a CPU, you won't pay twice as much for your PC. Of course, your own mileage may vary depending on which components you buy for a new system.

With total system costs factored into the picture, the race becomes even tighter. The Intel "line of values" remains intact, but AMD's offerings are right in the thick of things, although AMD's lineup doesn't extend as far up the price and performance axes as Intel's.

Despite the prevalence of apps that don't take advantage of more than a couple of cores in our benchmark suite, the Core 2 Quad Q6600 comes out looking very good, ahead of the dual-core CPUs we tested, not to mention each and every AMD processor. Once again, the Core 2 Quad Q9300 sits in a particularly nice spot, too. It lies comfortably above all cheaper and similarly priced offerings on the performance scale, but costs only $144 more than the cheapest config with an Athlon X2 5600+. Other quad-core CPUs don't look quite as appealing, and only the very expensive Core 2 Extreme QX9775 setup offers substantially higher overall performance.

Among the AMD processors, we should single out the Phenom X4 9850 for distinction. This CPU places well in our overall scatter plots, very close to two of the best Intel values in the Core 2 Duo 8400 and Core 2 Quad Q6600, and as we've mentioned, it comes with an unlocked upper multiplier for easy overclocking. As a result, AMD's highest performance processor may also be its most compelling overall value.

Of course, depending on your needs, a more (ahem) extreme solution may be a good value for you, as well. Relatively speaking, computer hardware is cheap. And time is money. If going with a more expensive CPU can save you several minutes or more each day, it may be worth every cent.