Fastest On-Chip Dynamic Memory Technology from IBM

Almost as an answer to Monday's announcement of Teraflops-chip by Intel, today IBM announced at the International Solid State Circuits Conference in San Francisco that it has devised a way to triple the amount of memory stored on chips and double the performance of data-hungry processors by replacing a problematic type of memory with a variety that uses much less space on the slice of silicon.

IBM's new technology, which is also designed in stress-enabled 65nm Silicon-on-Insulator (SOI) using deep trench, improves on-processor memory performance in about one-third the space with one-fifth the standby power of conventional SRAM (static random access memory). The new memory technology will help unclog crippling bottlenecks that build up as increasingly powerful microprocessors attempt to retrieve data from a separate memory chip faster than it can be delivered.

IBM said its solution entails swapping out most of the static random access memory, or SRAM, used to store information directly on computer chips and integrating onto the chip another kind of memory, known as dynamic random access memory, or DRAM. SRAM is a type of memory that’s fast and easy to manufacture but takes up a lot of valuable 'space' on the chips. DRAM, the most common type of memory used in personal computers, has typically been stored on a separate chip and has previously been viewed as too slow to be integrated directly onto the microprocessor.

The company has been able to speed up the DRAM to the point where it’s nearly as fast as SRAM, and that the result is a type of memory known as embedded DRAM, or eDRAM, that helps boost the performance of chips with multiple core calculating engines and is particularly suited for enabling the movement of graphics in gaming and other multimedia applications.

The prototype 500 MHz chip created by IBM was able to move data in and out of the memory in a random fashion in under 1.5 nanoseconds, which is a bit slower than SRAM--half as fast compared to the fastest SRAM on the market, in fact. But the embedded DRAM was considerably faster at dispensing data than normal DRAM, which can take almost 10 times as long to do the same task. Because DRAM has much fewer transistors and less memory leakage, IBM says it can cram 3 times as much DRAM cache on the chip, which will make up for some of the slowness of embedded DRAM compared to SRAM.

The technology is expected to be a key feature of IBM's 45nm microprocessor roadmap and will be included in IBM's server chips starting in 2008 and will expand to other products.