Ace's Hardware on DDR400 latency
I stumbled over some interesting information over at Ace's Hardware
regarding volume production of DDR400. Micron will be targeting latencies of 3-4-4 for its DDR400 modules as opposed to 2.5-3-3 for DDR333. They also expect DDR400 support to largely be limited to two DIMM slots. Samsung will apparently be doing similar things with its DDR400 memory, which leaves Winbond.
Right now, the only company which is able to produce DDR400 chips with low latencies is Winbond. The current 5ns Winbond chips are able to run at 200 MHz CAS 2.5 when mounted on a decent PCB. Corsair even managed to get 437 MHz out of these chips using top notch PCB and other components on their PC3500 DIMMs.
NVIDIA's nForce2 already supports DDR400, and it looks like even Intel will adopt the faster memory in its upcoming Springdale chipset. High-latency DDR400 may in fact be slower than low-latency DDR333. We'll have to see.