The number of dual-channel DDR platforms continues to increase, and has really created a subset of the memory market. The "matched pair" format is becoming increasingly popular, as these DDR module kits are perfectly suited for the requirements of high-end dual-channel DDR operation, and are a much safer buy than purchasing one module now and hoping to match it up later. The most popular configurations are the 2x256-MB and 2x512-MB kits, and with few exceptions, vendors offer the same basic speeds in matched pair DDR kits, as with their single module DDR.
The high-end matched pair DDR price list shows a few definite trends. The mainstream PC2700 and PC3200 modules are mostly stable this week, but the high-end PC4000 and PC4200 range is far more volatile. Thankfully, price cuts are in the order for most brands, and this is one area that you can find some relative deals.