Theory is wrong because Hyperthreading simply works by allowing the operating system to schedule two threads or processes simultaneously it does not mean the processor is capable of processing these theads at the same time. The technology improves processor performance under certain workloads by providing useful work for execution units that would otherwise be idle, for example during a cache miss. It is not working all the time at best increases performance by 30% which is a lot less than the 70% performance yield gained by adding another physical processor. More recently Hyper-Threading has been branded as energy inefficient using 46% more power which explains why the P4's always run so hot.

Dual core processors have the advantage that because the cache is shared between two closely located cores that the circuitry can operate at a much higher clock rate than is possible if the signals have to travel off-chip, however they still suffer from the same problems as generic multiple processing machine (SMP)... Other than demanding support from the Operating System (which Windows does not do fully) adjustments to existing software are required to maximize utilization of the computing resources provided by multi-core processors. Also, the ability of multi-core processors to increase application performance depends on the use of multiple threads within applications. For example, most current (2006) video games will run faster on a 3 GHz single-core processor than on a 2GHz dual-core processor (of the same core architecture), despite the dual-core theoretically having more processing power, because they are incapable of efficiently using more than one core at a time

I have a single core AMD overclocked in a Vapochill case with a 2gb Corsair XMS gigabyte iRAM drive and Geforce 8800 GTX SLI which would out benchmark most dual core gaming rigs simply because its strength and what is important for gaming is not raw power but bandwidth and I get this from the Geforce Graphic cards and the iRAM solid state drive