Intel's Strike Force: 19 DDR-Motherboards With 845 Chipset and DDR-Support

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Memory Matters: Why It Should Be DDR

RDRAM in the current PC800 standard will be replaced soon, as the performance benefits in contrast to DDR memory are gone. DDR-based chipsets like the VIA P4X266A, the SiS645 (this one even at 166 MHz memory clock) or the i845 offer similar or equal performance at reduced costs with respect to both the chipset and the memory.

In a few months, Intel will be offering the Pentium 4 for 533 MHz FSB . Simultaneously, a new RDRAM standard will appear (PC1066 at 533 MHz double-pumped), working perfectly synchronously with the clock speed. The first benchmarks proved that the team consisting of RDRAM + Pentium 4 makes much more sense than most of us imagined, and that common systems with DDR memory lag a bit behind. In this context, I would like to underline that we are talking of a price segment that is clearly higher than the one represented by these 19 motherboards. Both the new CPUs (2.4+ GHz) as well as the chipset and the memory will be available at lunatic prices. Only fat wallets, please.

So get ready for DDR as the old and new alternative! Though dual-channel PC1066 RDRAM will be quite a bit ahead of DDR memory, the latter will finally also work synchronously with the FSB. But DDR clock speeds could also be soon increased, bringing systems with 166 (DDR333) or even 200 MHz (DDR400) memory clock (double-pumped, of course).

Swipe to scroll horizontally

Header Cell - Column 0	RDRAM	DDR-SDRAM
Clock	400 MHz (double-pumped)	133 MHz (double-pumped)
Name of module	Rambus Inline Memory Module (RIMM)	Dual Inline Memory Module (DIMM)
Interface	16 Bit	64 Bit
Access	via a dedicated protocol	via classic memory grid
Bandwith	2 Byte (16 Bit) x 800 MHz= 1600 MB/s	8 Byte (64 Bit) x 266 MHz= 2133 MB/s
Bandwidth in real life	3.2 GB/sDual-Channel PC800 RDRAM	2.1 GB/sPC2100 DDR-SDRAM
ECC available?	yes	yes
Largest module available	512 MB	1 GB
Usage	Two RIMMs only. Empty slots have to be equipped with continuity RIMMs.	single
Performance Differences	Yes, 35 and 40 ns	yes, due to several memory parameters (e.g. CAS Latency)
Memory manufacturing costs	medium	low
Motherboards manufacturing costs	medium to low	medium to low
Platforms	Intel Pentium III, Pentium 4	Intel Celeron, Pentium 4, Pentium IIIAMD Duron, Athlon, Athlon XP, Athlon MPVIA C3

From the table above, you can tell that there are several advantages of DDR memory:

Better upgradeability: single DIMMs can be added
Availability on all platforms: when changing to an Athlon XP system, you can continue using your DDR memory
Larger modules allow larger maximum memory sizes

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Patrick Schmid was the editor-in-chief for Tom's Hardware from 2005 to 2006. He wrote numerous articles on a wide range of hardware topics, including storage, CPUs, and system builds.