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Sneak Preview: Intel Alderwood/Grantsdale Chipsets

Overview Of DDR Vs. DDR2

Source : Micron DesignLine Vol. 12, 3Q03

DDR2 : Speed

More interesting than the potential clock speeds are the bandwidths in dual channel operation that result from them (far right column) :

Memory TypeClock SpeedNameBandwidthSingle-ChannelBandwidthDual-Channel
DDR266133 MHz DDRPC21002,100 MB/s4,200 MB/s
DDR333166 MHz DDRPC27002,700 MB/s5,400 MB/s
DDR400200 MHz DDRPC32003,200 MB/s6,400 MB/s
DDR2 400200 MHz DDRPC2 3200*3,200 MB/s6,400 MB/s
DDR2 533266 MHz DDRPC2 4300*4,266 MB/s8,533 MB/s
DDR2 667333 MHz DDRPC2 5300*5,333 MB/s10,666 MB/s
DDR2 800400 MHz DDRPC2 6400*6,400 MB/s12,800 MB/s

* Source : Corsair website

8,533 MB/s (8.33 GB/s) in dual-channel operation is what we get with DDR2 533 - and this in itself sounds promising. However, there are two major factors that will fundamentally reduce the extra performance potential : firstly, the timings that have been possible up to now with CL 4 and 4-4-12 can still be increased ; secondly, at 533 MHz in the DDR process, the memory has to be run pseudo-synchronously to the 800 MHz FSB of the P4 (quad-data rate process) at a ratio of 2:3 - in the past, this has often proven to be an effort made in vain.