Intel Woodcrest, AMD's Opteron and Sun's UltraSparc T1: Server CPU Shoot-out

Conclusion

Two months of testing and tweaking allowed us to gather a lot of information. Our Sybase and DB2 tests still need a bit of tweaking before we can publish result on them, but with tests on SSL, JSP, LAMP, MySQL and PostGreSQL, what can we conclude so far?

Sun's T2000 server and it's 32 thread T1 CPU turned out very variable results. It is not the best choice for open source databases. PostGreSQL and MySQL scale better on Solaris than they do on Linux, but both RDBMS have trouble scaling over multiple cores. It is likely that the DB2 and Sybase results will be much better on the T2000. The SAMP web performance of the T2000 was good when we cached the PHP pages and we had few accesses to the MySQL database. When PHP pages had to regenerated with every access and the query cache of MySQL was used, performance was pretty bad compared to the x86 competition. The best purpose for the T2000 is a JSP server with SSL authentication.

The Intel Xeon 5160, a.k.a. Woodcrest, will simply be the most powerful server CPU this year (though it's not yet available for purchase of course). As our extrapolated calculations show, even a 2.6 GHz Woodcrest will outperform the current Opteron 285 with a 5 to 55% margin, nothing short of impressive. The new Xeon is however not invincible: the Opteron can still give some serious resistance when running some instruction mixes with lots of rotates, add-carry or load effective address instructions. RSA, AES and other benchmarks clearly show this. Intel will still have to convince some software vendors to port to SSE if it wants Woodcrest to be the completely superior CPU. The advantage in MySQL is also rather small, a result of the relatively high latency of the FB-DIMMs. But we are nitpicking: Intel's newest Xeon has taken back the performance/Watt crown. In one word: Woodcrest rocks!

And what about AMD? The Opteron remains a powerful architecture with a flexible platform. It is quickly becoming the most popular platform for 4 sockets and the upcoming Tulsa CPU is most likely not going to change that. However part of AMD's success has been Intel's Prescott/Nocona failure. In the K6 and Athlon (K7) years, AMD managed to improve the architecture every two years. In 1999 we had the original Athlon, in 2000 we got Thunderbird (integrated L2 cache) and in 2002 we got the Athlon XP. For the few past years, the Opteron architecture has made the move to dual-core and received a better memory controller, but the necessary IPC improvements and cache enlargements have not materialized. "Only the Paranoid survive", remember?

The Intel P-M architecture went from 1.7 GHz Single Core (Banias) in 2003 to 3 GHz (Conroe, Woodcrest) in 2006, while it quadrupled the L2 cache and significantly improved the IPC. At the same time, AMD's K8 series went from 1.8 GHz to 2.8 GHz dual-core, with the same amount of cache, and almost equal IPC. The result is that AMD will not be able to regain the performance crown in the dual and quad-core market until the K8L arrives. The future looks bright in the quad socket market however.

In summary:

Intel Xeon 5160 (Woodcrest)
Advantages:

• Best server performance across all applications
• Best Performance/Watt in the high end
• Absolutely stunning web server performance
• FB-DIMM enables high RAM capacity and bandwidth (quad channel)

Disadvantages:

• Needs SSE optimized code for some special case code (RSA, AES)
• FB-DIMM adds extra latency, cost (small) and power

UltraSparc T1 / Sun T2000
Advantages:

• Superb SSL performance
• Excellent Performance/Watt with SSL and Java code
• Solaris, a robust and well scaling OS
• Quad channel enables high RAM capacity

Disadvantages:

• Heavy optimizing is necessary; out of box software performance is low
• Low single threaded performance; also results in low performance in server software that scales badly
• Price/Performance compared to Woodcrest

AMD Opteron
Advantages:

• Well rounded CPU: performs well even with non optimized code; still excellent MySQL server results
• Excellent Quad socket platform
• Does not need FB-DIMM for high capacity thanks to NUMA

(DDR2 (socket-F) offers lower latency, less power and less cost )

Disadvantages:

• Web server performance compared to Woodcrest
• Power at higher clockspeeds (110 W vs. 80 W)