Dual Xeon Duo: What Good Is the L3 Cache?

Summary: Xeon 3.06's Added L3 Cache Does Little

In the workstation market, Intel has left its competition for alpha status, Sun & Co., in the dust. The Xeon processor in single or dual operation clearly dominates the market. But AMD looms large since the Opteron 244/246 for dual workstations became available on the market. Intel woke up and decided to add a 1 MB L3 cache to its top 3.06 GHz Xeon model - comparable to the sinfully expensive Xeon MP for server use. The same processor is also available without L3 cache as an option. There is a price difference of 33 percent: $690 vs. $455.

Our benchmark tests, which exactly reproduce workstation usage with appropriate applications, show that the additional L3 cache hardly adds any speed. Popular 3D software, such as 3D Studio Max, Cinema 4D and Lightwave, show no improvement in performance.

All in all, the fact remains that the Intel Xeon (workstation version) is forced to work with a lower FSB bandwidth compared to the Pentium 4 (4.2 GB/s, compared to 6.4 GB/s) and works at its maximum with a DDR333 memory. Performance loss occurred as a result of the asynchronous operation of FSB to memory bus. The highest clock speed was 3.06 GHz; P4 is already available with 3.2 GHz. Dual operation with corresponding software optimization provides the high computing performance needed in scientific/ technical settings. In the end, thanks to Hyper-Threading technology, four virtual processors are available.

To anyone faced with the choice of the dual Xeon 3.06 with or without the L3 cache, we would recommend the version without the additional cache. The additional cost is not justified.

The Pentium 4 has already shown us that increasing the FSB speed results in greater percentage gains in performance than increasing the memory speed. The successor to the Xeon, based on the Prestonia core, is still behind the starting gate: codenamed Nocoma and borrowing heavily from the Prescott core, an FSB speed of 166 MHz (FSB667) is expected to provide for more performance. Here's why: AMD's dual Opteron is breathing down its neck - as the benchmarks bear out impressively!