Q: 64-bit PCI - 66 Mhz vs 33 Mhz networking performance?

[Patrick Geoffray]

Don Holmgren wrote:

> The motherboards recently released for dual Pentium IV Xeons which are
> based on the i860 chipset have 64/66 PCI slots.  The ones that I know
> of are the Tyan Thunder-i860 and the SuperMicro P4DC6, as well as the
> motherboards used in the Dell Precision 530 and Compaq W8000.

i860 is cheesy. It has the 64/66 label but not the performance.

There is not a lot of choice for PCI 64/66 :
* ServerWorks: the best, very good PCI chipset.
* Intel i860: Don't wonder why Intel is using ServerWorks 
chipset for high-end servers.
Yes, the 760MP is 64/33.

For the future, ServerWorks is working on a P4 chipset and 
the 760MPX should be 64/66. I expecte very good perf from 
ServerWorks, but I have no clue about 760MPX PCI 
implementation.

For GigE or Giganet, 64/33 is good enough (peak at 250 MB/s, should 
support full-duplex bandwidth). For SCI or Myrinet, you really want 
64/66.

Regards

Patrick

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