DMI in Atom processor

[icoming]

Hello,

I noticed that some Atom processors use DMI to connect to memory. If I understand correctly, these Atom processors integrated memory control chip inside the processors. But I hope someone can help me clarify the memory accessing speed. For Atom N550 (http://ark.intel.com/Product.aspx?id=50154), DMI is 2.5GT/s. Does it mean the maximal memory accessing rate is 2.5*8=20GB/s if the memory is fast enough? If this is true, it seems this type of Atom processors can support much faster memory. Even DDR3 cannot be this fast.

Thanks,
Da

 

[archibael]

DMI does not connect to memory. It connects to the I/O and peripheral hub.

The memory controller on non-FSB Atoms is integrated and has nothing to do with DMI.

 

[icoming]

I see. For non-FSB Atoms, what can decide the maximal memory bandwidth? The speed of memory itself?
Sorry, maybe it's a very stupid question. I just get a little confused.

Thanks

 

[archibael]

The built in memory controller, the details of which are found in the datasheets themselves. For instance, for the N400 family:

http://download.intel.com/design/processor/datashts/322847.pdf

Page 13 shows maximum memory performance. There might be a better document which lists this easier, but I'm not finding one immediately.

 

[icoming]

I see. So integrating memory controller in CPU cannot really improve the memory bandwidth. The memory bandwidth on Atom processors are really slow.

 

[icoming]

Best answer selected by icoming.