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 list shows the same basic trends as the single-module prices, but with the natural magnification of buying dual modules instead of just one. Overall price levels are up across the board, and we're seeing quite a few double-digit price spikes. Kingston HyperX PC4000 2x512-MB, and OCZ PC4200 EL 2x256-MB were all up by over $20, and really mirrored the PC4000 and up price increases on the single-module side. If you're looking for deals this week, 512-MB kits and PC3200 1-GB kits are the places to start looking, as well as a select few of the high-end DDR kits.