We're Off: Memory Components
"The fastest memory device you’ve ever dreamed of" - that’s what we’d really like to know about.
With four DIMM sockets for conventional 184-pin DDR modules, the i-RAM accepts up to 8 GB of memory ; however, 2 GB DDR-DIMMs have been unobtainable until now.
Any DDR-DIMMs of the DDR266, DDR333 or DDR400 sort can be fitted. Although we found no information in the handbook about the actual clock rate of the modules, for reasons of compatibility we are assuming that it is at the most 133 MHz (DDR266). Gigabyte says that the work rate is 100 MHz, thus DDR200, since this clock speed is already good for up to 800 MB/s per 32-Bit DIMM. Multi-channel operation however is not supported by i-RAM - the theoretical and the practical bandwidth are therefore based on single channel DDR200. It appears to be similar for the memory timings : These are slow since the interface to the system would always thwart higher performance anyway. This would even be true if serial ATA II at 300 MB/s came into use. Features like command queuing in any case only make very limited sense for RAM drives.
Modules can be individually fitted and theoretically even mixed as far as capacities and speeds are concerned. Nonetheless, from experience we advise against mixing three or four different modules, instead sticking to two different memory modules at most. Ideally, of course, you would have four identical DIMMs, as we used for this test.
During our tests we further determined that a larger number of memory modules has some influence on the performance. With one and two DIMMs the maximum is obtainable, while with three and four DIMMs a slight decrease in performance was determined. More information is shown in the benchmark results further down in the article.
We used four Corsair 1 GB-DIMMs for the tests.
We installed four modules - the i-RAM is ready for use.