Advanced Micro Devices Inc (AMD)

[dacaw]

SPEC, cache & memory

From the same site as the Opteron fp unit discussion another article about the brouhaha over spec scores:

Quote: "The SPEC 2000 benchmarks are subject to much debate in the scientific community. Are they broken? Do they just depend on memory bandwidth? Do they fit entirely in the cache? "

http://www.chip-architect.com/news/2003_08_29_Cache_efficiency_for_SPEC2000.html

Note the comment in the final para:

"The memory footprint of the SPEC2000 benchmarks is less then 200 MByte to be able to run on systems with 256 MByte DRAM. Heavier applications using multiple Gigabyte structures are likely to see much greater degradations. AMD's distributed memory solution based on HyperTransfer links is likely to pay of in these cases. A four processor 2200 MHz Opteron may reach a similar SPEC2000_rate performance as a four way 1500 MHz Itanium 2 even though the latter has a much higher single processor score. Again, larger floating point memory footprints may skew the results even further. "