Replies to post #4073 on Rambus (RMBS)

[cordob]

Elixe, do I read correctly that there can only be 256 MB (now) of external memory?

at:
http://www.realworldtech.com/page.cfm?ArticleID=RWT021005084318
The obvious advantage of the XDR memory system is the bandwidth that it provides to the CELL processor. The less obvious drawback is that it is a memory system designed specifically for a high performance embedded system. Particularly, the maximum of 4 DRAM devices means that the CELL processor is limited to 256 MB of memory, given that the highest capacity XDR DRAM device is currently 512 Mbits. While the capacity of limit of 256 MB or even 512 MB of memory would not limit the expected primary application of the CELL processor, the capacity constraint does present itself as an issue in applications where large memory capacity is needed alongside high DP FP throughput and high bandwidth. Clearly, the CELL processor is currently not suitable for these environments, but the high speed FlexIO may enable the use of an external memory controller where multiple channels of high frequency, Fully Buffered Dimms may be attached to retain the bandwidth capability but solve the capacity constraint issue. Incidentally, Toshiba is a manufacturer of XDR DRAM devices. Presumably it brought the XDR memory controller and memory system design expertise to the table, and could ramp up production of XDR DRAM devices as needed.

Btw indeed an excellent article, thks for the link.

Cheers
Cor