Choosing the CPU

Before I even thought about building anything, I came up with a benchmark suite designed to stress all components of a system, with a combination of real-world dual and single processor tests which we’ll go over later. At the moment I’m writing this paragraph, I have no clue which CPU platform is going to give the best overall performance on my test suite. That’s why we’re building these systems – to benchmark them. It’s unreasonable to write an article covering the build of multiple systems, so I’m going to focus on the Dual Opteron 246 system in this article. Common sense would expect this system to do very well given that it’s the most expensive, but more importantly, you’ll learn the most about system building in general by reading about the AMD64 build.

AMD Opteron

In our lab, we’re getting a 16 CPU Opteron 240 cluster running Scyld Beowulf Professional with bonded Gigabit Ethernet interconnects (with 8 nodes, exotic interconnects aren’t as important). The nodes are BOXX Technologies RenderBoxx R4’s. Our lab standardized on AMD64 given that our commercial LS-DYNA software is scheduled for AMD64 support, and our memory needs exceed 4GB.

This workstation will need to have excellent gaming performance, so I obtained the fastest Opteron CPUs I could – the Opteron 246.

For our low-noise AMD, the CPU cooler design win went to the Zalman CNPS7000-AlCu. This hybrid aluminum-copper processor cooler features a large 92mm cooling fan. By using a low-RPM, large-diameter fan with a high-surface area heatsink, noise is kept to a minimum. Going with the aluminum/copper hybrid rather than the copper only heatsink was important for two reasons:
1) The copper version weighs over one pound, increasing the potential for damage when moving the system
2) Though copper conducts heat quickly away from the CPU, it also is tougher to cool down. When the Zalman coolers are run in the low-RPM silent mode, the fans are spinning slowly enough where the –AlCu and –Cu coolers are very close in performance. Even at full speed, the difference in performance is more for bragging than overclocking or system stability.

Close Up of CNPS7000-AlCu

Both CPUs in view