memory bandwidth on Athlon systems

[Brian D. Haymore]

Guignon Thomas wrote:
> 
> Hello,
> We have recently received an Athlon 700 system (Abit KA7 + 2 x 512M
> pc100) and stream benchmark give poor results (even when using
> turbo mode) compared to my old K7M with an Athlon  600. Here
> are the results:
> 
> zephyr: 700 kx133 pc100 turbo (2x512) ABIT KA7
> -------------------------------------------------------------
> This system uses 8 bytes per DOUBLE PRECISION word.
> -------------------------------------------------------------
> Array size = 999936, Offset = 0
> Total memory required = 24.9 MB.
> Each test is run 10 times, but only
> the *best* time for each is used.
> -------------------------------------------------------------
> Your clock granularity/precision appears to be 1 microseconds.
> Function      Rate (MB/s)   RMS time     Min time     Max time
> Copy:         302.8281       0.0529       0.0528       0.0530
> Scale:        300.8701       0.0533       0.0532       0.0533
> Add:          342.1093       0.0703       0.0701       0.0714
> Triad:        338.7202       0.0709       0.0709       0.0709
> 
> copernic: 600 amd750 pc100 (1x128) ASUS K7M
> -------------------------------------------------------------
> This system uses 8 bytes per DOUBLE PRECISION word.
> -------------------------------------------------------------
> Array size = 999936, Offset = 0
> Total memory required = 24.9 MB.
> Each test is run 10 times, but only
> the *best* time for each is used.
> -------------------------------------------------------------
> Your clock granularity/precision appears to be 1 microseconds.
> Function      Rate (MB/s)   RMS time     Min time     Max time
> Copy:         358.9613       0.0447       0.0446       0.0450
> Scale:        436.5540       0.0367       0.0366       0.0368
> Add:          447.4549       0.0537       0.0536       0.0537
> Triad:        451.6738       0.0533       0.0531       0.0535
> 
> As you see the old system is by far superior to the new one.
> I wonder if anyone has some experience with the Abit KA7 to help me
> solving this problem?
> 
> A+
> --
> Thomas Guignon (guignon at asci.fr)
> Laboratoire ASCI, ORSAY(France), www.asci.fr
> #####
> 
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Move up to the RY bios release, it is beta but proves to be fairly
stable.  With the RY set the memory interleaving to 4-way and that
should help out a lot.  I have 34 950 Mhz Athlon systems with ABIT KA7
boards and have 256MB PC-133 modules in them.  When I set them to PC-133
with the 10ns SDRAM timings and 4-way interleaving this is what I get.


-------------------------------------------------------------
This system uses 8 bytes per DOUBLE PRECISION word.
-------------------------------------------------------------
Array size = 10000000, Offset = 0
Total memory required = 228.9 MB.
Each test is run 10 times, but only
the *best* time for each is used.
-------------------------------------------------------------
Your clock granularity/precision appears to be 1 microseconds.
Each test below will take on the order of 244740 microseconds.
   (= 244740 clock ticks)
Increase the size of the arrays if this shows that
you are not getting at least 20 clock ticks per test.
-------------------------------------------------------------
WARNING -- The above is only a rough guideline.
For best results, please be sure you know the
precision of your system timer.
-------------------------------------------------------------
Function      Rate (MB/s)   RMS time     Min time     Max time
Copy:         458.0563       0.3512       0.3493       0.3550
Scale:        457.9331       0.3503       0.3494       0.3518
Add:          526.3619       0.4586       0.4560       0.4595
Triad:        537.3515       0.4503       0.4466       0.4519

--
Brian D. Haymore
University of Utah
Center for High Performance Computing
155 South 1452 East RM 405
Salt Lake City, Ut 84112-0190

Email: brian at chpc.utah.edu - Phone: (801) 585-1755 - Fax: (801) 585-5366