Expensive Quad Sockets vs. Ubiquitous Dual Sockets

SAP S&D 2-Tier

The SAP SD (sales and distribution, 2-tier internet configuration) benchmark is an interesting benchmark as it is a real world client-server application. We decided to take a look at SAP's benchmark database. The results below all run on Windows 2003 Enterprise Edition and MS SQL Server 2005 database (both 64-bit). Every "2-tier Sales & Distribution" benchmark was performed with SAP's latest ERP 6 enhancement package 4. These results are NOT comparable with any benchmark performed before 2009. The new "2009" version of the benchmark obtains scores which are 25% lower. We analyzed the SAP Benchmark in-depth in one of our previous server oriented articles. The profile of the benchmark has remained the same:

• Very parallel resulting in excellent scaling
  
• Low to medium IPC, mostly due to "branchy" code
  
• Somewhat limited by memory bandwidth
  
• Likes large caches (memory latency!)
  
• Very sensitive to sync ("cache coherency") latency

And here are the results:

Some of you may have already made this analysis: the one year old Quad Xeon platform is outperformed by servers which are three times cheaper. The best dual Xeon makes the Quad Xeon look ridiculous as it outruns the latter by 15%. The Quad Opteron 2389 2.9 is getting a beating too, but his big brother, the Opteron 8435, takes revenge by running circles around the Intel hex-core: it is no less than 50% faster!

While performance is not the only factor to consider, the least you expect from a quad platform is that it offers somewhat better performance than a cheaper dual socket. This is exactly what we have been discussing in our "General IT" blog: the hex-core Opteron may tip the balance back in favor of a quad socket platform for a part of the server market. We are not impressed by the 30% performance advantage of a 24-core over an 8-core, and those looking for the highest raw performance will probably be disappointed. But for a large part of the market, performance is only one of the factors, and the 30% extra may well be good enough to convince people to consider a quad socket platform. Other factors like more memory and expansion slots, slightly better RAS capabilities and less power for the same number of applications might make a quad socket server a better choice for those people.