Dual Xeon Duo: What Good Is the L3 Cache?

Intel Xeon: Broad Product Range From $455 To $3692

Currently the Xeon processor is available in five different versions. First, there is the workstation version (codename: Prestonia) with 512 kB L2 cache - the structure is identical to that of the P4 (Northwood core). The only difference is the option of dual CPU operation. Moreover, for several weeks an expanded version has been available, with an additional 1 MB L3 cache. Both of the types mentioned are available with a maximum of 3.06 GHz and work with a FSB speed of 133 MHz (or FSB533, in Intel jargon). Among the high-end products with the highest profit margins are the three server Xeons which offer a 512 kB, 1 MB or 2 MB L3 cache. However, the FSB speed is limited to 100 MHz. In this test we concentrate on workstation use and compare two dual Xeon systems. While one system works with CPUs without an L3 cache, the second computer has processors with 1 MB L3 caches.

The top-of-the-line Xeon prices start at $455, which gets the customer the beginner-level 3.06 GHz Xeon without an L3 cache. After all, it is a P4 with the same clock speed for dual operation.

The version with the L3 cache costs $690 and is comparatively inexpensive, as the top-model Xeon MP with a 2 MB L3 cache and 2.8 GHz costs $3692. That means it is no longer much cheaper than the high-end Itanium 2 (1.5 GHz and 6 MB L3 cache), which eats up operating budgets at a hefty $4226.