Intel Cranks Up Xeon Clocks, Caches

by Timothy Prickett Morgan

Several weeks ago, when Intel announced its 64-bit extensions to the Xeon family of processors, the company said that it had delivered a boosted Xeon DP processor and two more variations on the "Presontia" theme. These announcements got lost in the shuffle, so Intel talked about these processors yesterday as it delivered a new "Gallatin" Xeon MP processor for high-end servers with a larger 4 MB L3 cache memory and a 3 GHz clock speed. These are then engines behind the Windows and Linux server markets.

This is the end of the line for Gallatin, which will be followed by the "Potomac" 64-bit Xeons in early 2005. These peppier Gallatins announced yesterday will plug right into any machine that currently uses this family of Xeon MP processors. This includes four-way machines made by the big tier one suppliers--Hewlett-Packard, Dell, IBM, and Fujitsu Siemens--as well as myriad white box vendors who compete vigorously for business in the midrange X86 Linux and Windows server markets. These Xeon MPs are also used in machines that couple 8, 16, or 32 processors together in a giant SMP cluster. They are not used in smaller two-way or uniprocessor machines, which have their own Xeon DP and Pentium 4 variants that run faster and offer better bang for the buck.

According to Alan Priestly, strategic marketing manager for Intel in the UK, Intel does not have any plans to add new Gallatin processors to the Xeon line in 2004 beyond the three processors that were announced yesterday. This is because it takes a long time to ramp up production processes on the Xeon MP chips, which are among the largest chips that Intel makes, and because the qualification processes that vendors go through take a long time because of the complexity of the midrange and enterprise machines that use them compared to entry servers that use Xeon DPs. That is why, says Priestly, the Xeon MP product launches tend to be on a six-to-nine month cycle. And knowing that Gallatin is the last of its line and that cycle time on launches, we now know that Intel is shooting for the Potomac kicker to Gallatin in early 2005. It looks like Intel is stretching the Gallatins for a bit longer than it might otherwise like. But Potomac is not going to do anyone much good until 64-bit versions of Linux and Windows tuned for Xeon-64s are available anyway, so there is not much point in hurrying.

In any event, there are three new Gallatins, which all have 400 MHz front side buses like the other Gallatin and "Foster" Xeon MPs. (Foster was the original Pentium 4 Xeon chip for high end servers.) The new 3 GHz/4 MB L3 cache Gallatin replaces the 2.8 GHz/2 MB cache Gallatin, and has the same list price at $3,692 each in 1,000-unit quantities. Intel is also announcing a 2.7 GHz/2 MB part, which at $1,980 each in 1,000-unit quantities is half the price of the 2.8 GHz/2 MB part. A new 2.2 GHz/2MB part costs $1,177, less than a third the price of the 2.0 GHz/2 MB Xeon MP that was the top-end machine 18 months ago. While the performance boost is always a welcome thing at the high end of the Xeon MP range, the price/performance increases for slower chips is what makes Xeon MP processors affordable for a growing number of companies. At these prices, four-way computing with powerful machines is an option for companies who could not even have pondered it a few years ago.

Priestly says that customers moving from 2.8 GHz/2 MB Gallatin parts up to 3 GHz/4 MB Gallatins should see about a 15 percent performance boost on Java and other threaded applications, and about a 25 percent performance on ERP-style workloads that are sensitive to cache memory. In general, the other two Gallatins offer about 10 to 15 percent more performance than the other Gallatins they replace at the same price point but with lower clock speeds and 1 MB L3 caches.

According to benchmark results shown by Intel, the larger cache on the new Gallatins can increase the effectiveness of HyperThreading (HT) by a few percent because the cache decreases latencies in gathering data. HT boosted the performance of the TPC-C transaction processing benchmark by 10 percent on a four-way Foster Xeon MP running at 1.6 GHz and with a 1 MB L3 cache. On the 3 GHz/4 MB Gallatin, HT boosted performance on this box by 13 percent. On the SAP R/3 S&D benchmark, that same Foster machine saw only a 5 percent performance boost with HT activated, but the Gallatin 2.8 GHz/2 MB machine saw a 14 percent increase. Presumably a 3GHz/4MB part might even see an HT increase that is even larger. On the SPECjbb2000 Java benchmark, the Foster chips saw a 19 percent increase in performance, while the Gallatin 3 GHz/4 MB with nearly twice the clocks and four times the L3 cache only saw a 16 percent gain from HT.

The new Gallatin chips will be available starting yesterday, and have been validated by Intel's OEM partners, according to Priestly.

On the Xeon DP front, Intel has three new parts: a 2.4 GHz/1 MB chip, a 2.8 GHz/1 MB chip, and a 3.2 GHz/2 MB chip. Like the other past generations of Prestonia chips, these have a 533 MHz front side bus. The top-end 3.2 GHz/2 MB Prestonia has about a 10 percent performance benefit compared to the 3.06 GHz/1 MB Prestonia, according to Priestly, and at $1,043 each per 1,000-unit quantities, it carries a hefty 51 percent premium compared to that slower Prestonia, which costs $690. The new 2.8 GHz/1 MB Prestonia costs $455, the same as its 3.06 GHz/512 KB predecessor, while the new 2.4 GHz/1 MB Prestonia costs $316, the same as a 2.8 GHz/512 KB part.

This is the last in the line for the Prestonia chips, too, by the way. The next stop on the Xeon DP train is the "Nocona" Xeon chip, which is due in the second quarter and which will be the first Xeon chip to implement 64-bit extensions.