Dual DDR: Following The Footsteps Of RDRAM
Doubling the memory bandwidth by using two banks simultaneously is actually not a new thing. This is completely normal, even for its bitterest rival, RDRAM: only the combination of two 16 bit RIMMs will bring the memory interface to the necessary 32 bits. The E7205, however, offers two separate memory controllers in the hardware that can process the main memory data simultaneously and yet independently of one another.
In connection with a current Pentium 4 processor, this approach makes particular sense, since HyperThreading imitates a dual-processor system, and in many cases, can even be parallel.
Dual DDR266 Vs. Single DDR333
In our technology article we compared Granite Bay not only with the 850E chipset but also with the 845PE, which works with DDR333. And in fact, depending on how you use it, there are cases in which our test system with a single-channel DDR333 worked faster than a Granite Bay system with dual-channel DDR266.
So why didn't Intel just use a dual-channel memory interface for DDR333? For one thing, the market leader is not necessarily an advocate of DDR-SDRAM. Rambus DRAM would have dominated the market if it hadn't been for the countless protests against the polarizing memory architecture. For another, Intel supports asynchronous memory operation (memory at FSB speed), if there is no alternative. This happened with the 845 chipset (DDR266 with 133 MHz at 400/ 100 MHz FSB speed), which had to suffice as an alternative to the unpopular 850 chipset, and with the 845PE, whose memory interface was released for 166 MHz (DDR333) for performance reasons - although the FSB of the Pentium 4 still stands at 400/ 100 or 533/ 133 MHz.
