This second part of our article series on parallel processing dealt with single and dual channel memory, as well with the possible performance gains of upgrading a single hard drive to a RAID array with two or four hard drives. In "Parallel Processing, Part 1: CPU Cores" we analyzed where and how dual and quad core processors can increase performance, and we concluded that it makes the most sense to stick with a dual core processor for now, and only purchase a quad core if your applications can actually benefit from it. In the end, the 45 nm generation code-named Penryn is due at the beginning of next year, and it will deliver somewhat more performance at decreased power requirements.

But back to RAM and hard drives. As expected, the performance difference between single channel and dual channel DDR2-800 memory using an up-to-date Core 2 Duo system is little to nil, depending on the benchmark - most tests show differences, but they are really small. For games and enthusiast PCs, we recommend sticking to high-performance dual channel RAM, because the memory is one of those components that you want to perform best for a smooth experience. For regular applications, though, it doesn’t really matter much whether you run single or dual channel. Two 1 GB DIMMs typically are cheaper than a single 2 GB module, but a single DIMM will reduce your power consumption by several watts (which might just be more interesting than it is important).

It’s similar in the hard drive corner: a RAID array has to live with a marginal performance impact due to the added controller, which results in slightly decreased performance in several benchmarks. Benchmarks that actually benefit from increased storage throughput will show the best result when going from a single drive to a RAID 0 with two drives. Running four drives still increases the storage-intensive benchmarks, but the extra gains are comparatively small.