We already described most of the Pentium Dual Core facts in the intro and the second page of this article. The Pentium Dual Core E2000 family is available at three different stock speeds: the E2140 runs at 1.6 GHz, E2160 is the 1.8 GHz part and E2180 works at 2.0 GHz. All of them utilize a 200 MHz system clock (FSB800) and the Core 2 microarchitecture. When compared to Core 2 Duo with its 2 MB or 4 MB L2 cache, the Pentium Dual Core comes with only 1 MB, and it also doesn't support the virtualization technology called VT.
The three models currently cost approximately $79, $89 and $99. We doubt that the 2.0 GHz model overclocks better, because the Pentium Dual Core is nothing more than a Core 2 Duo with reduced L2 cache and clock speed due to having failed at certain tests. The third possibility, which would be Intel reducing the L2 cache size and clock speed to provide more low-cost processors requested by large customers, certainly is the best one for end users, because it implies that even clock speeds far beyond 3 GHz could still work...
We were able to run our E2160 retail processor at up to 3.3 GHz. However, the processor wasn't sufficiently stable at this speed, so we switched to 3.2 GHz for benchmarking. To reach this clock speed, we simply set the FSB speed to 355 MHz. As expected, we had to increase the core voltage from 1.325 V to 1.525 V. Applying more voltage (we tried 1.55 and 1.6 V) didn't lead to better overclocking results.
There is a nice advantage to accelerating the FSB speed within the capabilities of the motherboard, or only slightly beyond (355 instead of 333 MHz), which is the modest overclocking of the memory. The DDR2 RAM operated at DDR2-880 speed. Although it didn't cause any problems, we decided to increase the memory voltage anyway, just as a precaution.
The 3.2 GHz final clock speed represents an almost 80% overclocking over the base clock speed of 1.8 GHz. Since the 80% applies to both to the core clock and the FSB speed, it's difficult to say which is the actual bottleneck. We decided to sit back, relax, and watch the benchmarks. Complaining that an 80% overclock isn't enough for a $89 processor would be somewhat weird anyway!