Re: I think INTC is erring by not hanging with RMBS
An RDRAM channel is as wide, and as expensive in terms of motherboard costs, as a DDR channel. RDRAM traces are speced at half the impedance, and exactly twice the width, of DDR traces. RDRAM traces also require a grounding trace between data traces, doubling the distance that must be maintained between the twice as wide traces. The net result is that a 16bit RDRAM channel uses as much motherboard space, and is as difficult to route and expensive to manufacture, as a 64bit DDR channel.
Still, some dimwits continue to compare a much more expensive implementation of RDRAM with an economical to produce and easy to route DDR implementation - and the economical DDR implementation is nearly as fast as the expensive RDRAM implementation.
As CPU speeds increase, memory performance will have to be increased. For DDR that's rather simple - move from one channel to two channel.
That's what Intel is doing with their high performance chipsets going forward.
For Rambus, there is really no where to go. Laying out a 4 channel motherboard, which would be necessary to compete with a two channel DDR motherboard would probably require 8 layers - and such boards are very expensive to manufacture. Such a board would still support twice the bandwidth and lower latency, at the same cost, if it used DDR instead of Rambus.
Rambus has run into a dead end - that's why Intel dropped it. |
