Dell 1600SC + 82540EM poor performance..HELP NEEDED

Gerry Creager N5JXS gerry.creager at
Thu Jul 24 09:47:22 EDT 2003

And for the 802.3u impaired, you need to A) either set speed and duplex 
settings on your switch AND NIC to fixed values (preferably matching 
each other) or B) leave them all at Auto/Auto for switch and NIC(s).

For those who haven't wandered past the negotiation between switch and 
NIC recently, if you fix any value, negotiation will fail and the 
devices will go to default settings, ie., something resembling a 
consistent speed between the 2 and half-duplex.  But not even that is 

Note that I've also received recent reports of horrid GBE performance on 
Serverworks botherboards with the internal E-1000 NIC.  I've not been 
able to identify a cause (Don?  Thoughts?  Definitive info?) but I've 
been able to reproduce it.


Jeff Layton wrote:
> Stephane,
>   What kind of switch (100 or 1000)? Have you looked
> at the switch ports? Are they connecting at full or half
> duplex? How about the NICs? You'll see bad performance
> with a duplex mismatch between the NICs and switch.
> Are you forcing the NICs or are they auto-negiotiating?
> Good Luck!
> Jeff
>> Hello,
>> We have recently received 48 Bi-xeon Dell 1600SC and we are performing 
>> some benchmarks to tests the cluster.
>> Unfortunately we have very bad perfomance with the internal gigabit 
>> card (82540EM chipset). We have passed linux netperf test and we have 
>> only 33 Mo
>> between 2 machines. We have changed the drivers for the last ones, 
>> installed procfgd and so on... Finally we had Win2000 installed and 
>> the last driver
>> from intel installed : the results are identical... To go further we 
>> have installed a PCI-X 82540EM card and re-run the tests : in that way 
>> the
>> results are much better : 66 Mo full duplex...
>> So the question is : is there a well known problem with this DELL 
>> 1600SC concernig the 82540EM integration on the motherboard ????
>> As anyone already have (heard about) this problem ?
>> Is there any solution ?
>> thx for your help

Gerry Creager -- gerry.creager at
Network Engineering -- AATLT, Texas A&M University	
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.847.8578
Page: 979.228.0173
Office: 903A Eller Bldg, TAMU, College Station, TX 77843

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