What exactly is dual channel DDR ? Do I have to get special new memory modules for it or can I just use the normal DDR 400 memory modules ? Some please give me some kinda details on dual channel DDR
Dual channel DDR is essentially interleaving two DDR memory busses, effectively doubling the bandwidth. It uses standard DDR memory, but you will need a motherboard that supports it (NForce 1/2, Granite Bay and upcoming SIS/VIA), in addition they have to be installed in pairs (i.e. 512MB would be two 256MB sticks installed at banks 1&3 or 2&4).
check out this preview of the upcoming Gigabyte board using the granite bay chipset... quite impressive and they touch on the dual channel ddr. Here's the actual info so you don't have to read the whole damn thing: "There are a total of four DDR DIMM slots on the GA-8INXP. In fact, all Granite Bay boards will have four of these slots. You can install single DIMMs here but you'll get only single channel DDR performance. However, if you install them in pairs, the board will switch to two channels and give you performance on-par with PC1066. Unlike RDRAM, you do not need any termination. Oh, according to Gigabyte, the board would support dual channel DDR333 too. But that is if you're overclocking the front side bus to 667MHz. Now, if that's true, we might just see Pentium 4 processors coming in 667MHz FSB flavors very soon. Won't be surprised overclockers will be doing that way before Intel releases 667MHz FSB processors."
Dual channel DDR effectively doubles the bandwidth available through the memory subsystem. As mentioned above, there are Dual channel systems available for the Pentium 4 and the Athlon. However, with the P4, the memory system had always been the bottleneck. The FSB has a bandwidth of 4.2GBits/s which was only filled recently with 1066 RDRAM. However, Dual channel DDR 266 work syncronous with the FSB while offering 4.2 GBits/s. On the other hand, the athlons have been limited by the front side bus, and were already struggling to cope with the bandwidth available from single channel DDR. One of the reasons why the nForcedidn't offer the huge performance gains promised to us. Upping the FSB to 166MHz on the Athlon will definitely help to take greater advantage of the improved memory bandwidth available, but I think, at the moment, the P4 is in a better position to benefit from Dual channel DDR, particularly when springdale arrives next year with Dual DDR 400MHz accompanied with 800MHz FSB Processors!!!!!
