Intel returns to DDR for dual socket Xeons

PLENTY OF NOISE was heard over Intel's decision to create the FB-DIMM specification and, over the past year or so, make it the sole memory available on its Core 2-based DP and now MP platforms.

FB-DIMMs consume quite a bit more power with commensurate heat (RAM fan is a necessity, not an option, on these), the AMB chip in there adds a bit of latency as well - although, with recent version, nearly the same as typical registered DIMM, and, well, these modules ain't cheap by any measure.

Even the brand new FBD-800 low-voltage DIMMs, while taking care of performance and power/heat issues, don't exactly solve the price problem.

So, while we deliberated whether Intel drops the FB-DIMM's in Nehalem in exchange for on-board buffering, or simply introduces FBD-2, we know that there will be a 'standard registered DDR2' dual FSB chipset this year for the Xeon users in need of affordable standard memory expansion.

This new Intel entry, the San Clemente chipset, will not replace the FSB1600 Seaburg on the Stoakley platform - instead, San Clemente is the entry-level, dual FSB1333 chipset with dual-channel DDR2-667 registered memory. This means it has only half the memory bandwidth of the old Bensley platform, but with much cheaper and a tiny bit lower-latency memory.

This version should come out sometime in November, while an updated FSB1600 speed upgrade with DDR2-800 memory should see the light of the day by end of 1Q 2008.

Several Taiwan vendors will have comparably low cost ATX-sized San Clemente mobos, aimed mostly at entry level dual-socket workstation/server environment, before yearend, with up to 6 DIMM sockets (12 GB RAM with standard 2 GB modules, or 24 GB with many times more expensive 4 GB ones). So, until Nehalems arrive around Computex 2008 time, the Xeon dual socket high end will be reserved for FB-DIMMs, whether you like it or not. µ