AMD claims memory controller breakthrough

AMD has unveiled a new memory controller system which it claims will double the memory capacity on its high-end server and workstation systems.

The G3MX technology will target memory intensive systems such as virtualisation servers and large databases when it becomes available in 2009.

In conventional systems, Ram modules connect directly to a memory controller on the motherboard or are built into the CPU.

In larger systems requiring more memory, a buffer must be used between the memory module and the controller to avoid a decrease in performance. The current choice for this is fully-buffered Ram modules which contain a built-in buffer.

But the problem with fully buffered Ram is that it is expensive and power-hungry, and hampers performance, explained Nathan Brookwood, principal analyst at Insight64.

"Fully buffered Dims were thought to be a big thing, and they turned out not to be," Brookwood told said. "Every memory chip paid a price in terms of latency."

AMD's G3MX system attempts to solve this problem by replacing the buffers on the memory modules with an onboard buffer that handles four modules at once.

The result is a performance increase and a doubling in the number of Dimms that each CPU can handle from eight to 16.

"By installing the memory buffers, we can extend the existing memory channels of these future processors and run the interface faster, moving more data down it," Diane Stapely, strategic manager for Opteron systems at AMD, said.

Brookwood said that the technology offers benefits beyond the database and virtualisation servers that AMD is targeting. Multi-core CPUs may also have an impact.

"As you have more cores you need more memory, and pretty soon you need more modules than you can control through current interfaces," he explained.

"You cannot put more memory controllers on easily, so you need to go on some serial approach."

G3MX has another advantage in that it uses cheaper SD3 Dimms rather than specialised fully-buffered memory modules, Brookwood noted.

The analyst warned, however, that G3MX should not be crowned as a game-changing technology just yet.

While it appears to address the issues of fully-buffered Dimms, the new technology is far from battle tested and new weaknesses are likely to appear.

Brookwood also pointed out that AMD is not alone in the buffered memory field. Rival chipmaker Intel is rumoured to be working on a similar product.