Memory: Memory Interface And Quad-Channel
Current desktop chipsets are equipped with a dual-channel memory interface. The 5400, on the other hand, sports a quad-channel memory interface, allowing it to access four memory modules simultaneously. Theoretically, the memory bandwidth should thus be much higher than that of the desktop chipset. However, this is not the case.
Since the 5400 Northbridge also has to manage several other additional tasks that are not normally required of a desktop chipset, its overall performance is reduced.
For example, it runs error checking routines such as ECC. Then, there is also the snoop filter, which improves the utilization of the front-side bus. Additionally, the 5400 Northbridge has to manage two processors through two separate FSB interfaces while also communicating with the Southbridge through a separate ESI bus.
All of these additional features together affect performance to such an extent that the memory bandwidth of this quad-channel interface is effectively lower than that of a desktop chipset.
According to the measurements, the memory interface and the FB-DIMMs are optimized for fast writes and short access times. In these areas, the 5400 Northbridge and its memory do outpace the desktop chipset at the specified memory clock speeds. When reading from memory, it offers only half the bandwidth of its desktop counterpart, though.
Write performance of the FB-DIMMs doubles thanks to the quad-channel memory interface.
Quad memory channels
Intel's Skulltrail board features a quad-channel memory interface.