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Overclocking Intel's Xeon X3320 processor


For servers, workstations, and overclockers too?
— 12:52 AM on April 16, 2008

Manufacturer Intel
Model Xeon X3320 2.5GHz
Price (Street)
Availability Now

We PC enthusiasts have been co-opting enterprise-class hardware for our own personal systems for years now. We got our first taste of the creamy smoothness of SMP on dual-socket workstation boards long before you could get two cores conveniently packaged on the same chip. Tempted by lightning-fast access times and 10K-RPM spindle speeds, we adopted Western Digital's Raptor hard drive. And who can forget AMD's Toledo-based dual-core Opterons—overclocking marvels compatible with the same 939-pin socket as Athlon 64 X2 desktop chips. I've had what was a relatively inexpensive Opteron 165 designed to run at 1.8GHz happily chugging away at 2.4GHz on a standard desktop motherboard for a couple of years now.

Although they share the same architecture and performance characteristics as their desktop counterparts, server and workstation processors like the Opteron typically undergo additional validation testing and run at lower operating voltages. In a sense, chips that make the grade for the enterprise world are the best of the breed. That doesn't guarantee overclocking success, but it at least hints at untapped potential. When that potential plugs into a standard desktop motherboard loaded with overclocking options, we just can't resist.

It's no wonder, then, that Intel's Xeon X3320 caught my eye recently. This LGA775 chip features a 45nm Yorkfield core running at 2.5GHz with 6MB of L2 cache, making it the Xeon equivalent of the Core 2 Quad Q9300. What's more, while the Q9300 has been in short supply of late, the X3320 has been more consistently available at roughly the same price.

Few things make us happier than forcing normally conservative enterprise-class hardware to jump through flaming enthusiast hoops, so we scored an off-the-shelf Xeon X3320 retail box from the folks at NCIX to see what kind of overclocking headroom we could find. Read on for the surprising results.


Penryn dons a suit
The key to overclocking server and workstation processors is finding ones compatible with standard desktop motherboards. AMD and Intel both employ different socket designs for some of their enterprise-class chips, and the server and workstation motherboards they slip into tend to be completely devoid of overclocking options. Fortunately, Intel's Xeon 3000 series uses the same LGA775 package as desktop Core 2 chips, so you should be able to plug them into any motherboard that's compatible with their desktop equivalents.


The quad-core members of the Xeon 3000 series derived from Intel's new 45nm Penryn core are a part of the Xeon X3300 line, which includes the 2.5GHz X3320, the 2.66GHz X3340, and the 2.83GHz X3360. All three run on a 1333MHz front-side bus and are rated for a thermal design power of 95W. While the Xeon X3340 and X3360 each have a total of 12MB of L2 cache (6MB per dual-core component), the X3320 must make do with only 6MB of L2 (3MB per dual-core component).

The Xeon X3320's specs exactly match those of the Core 2 Quad Q9300, and their prices are comparable. You can find the Xeon online for as little as $290, while the Q9300 can be had for around $285. So what's the difference between the chips then?

Well there's the seal of approval that additional validation testing ostensibly provides, of course. Quantifying any difference in operating voltage between desktop and enterprise chips is a little more difficult now that Intel sets default voltages on a per-chip basis. However, I can tell you that CPU-Z reports our X3320's default voltage as 1.12V. We also have a Q9300 in house for testing (look for a full review soon), and its default voltage is 1.2V.


Another difference between Intel's desktop chips and their Xeon counterparts is the cooler bundled with retail-boxed CPUs. The Xeon's heatsink is a low-profile design that measures only 45mm tall (1.77 inches for the metric-impaired) to allow it to fit into rack-mount enclosures with less headroom.


The cooler features a copper core and the same basic design as the heatsinks bundled with desktop Core 2 processors, just in a much lower profile. The heatsinks bundled with Intel's desktop chips typically measure 60mm tall (2.36 inches).


To give you an idea of the size difference between Core 2 and Xeon heatsinks, we've lined them up with Scythe's popular Ninja cooler. The fans on the Intel coolers are similar in size, but the Xeon's heatsink is half the height—and therefore has half the surface area—of its desktop brethren.

The Ninja is just a monster by comparison, but it's relatively inexpensive and a worthwhile upgrade over the Xeon's stock cooler if you're going to be overclocking. Obviously, the Ninja offers significantly more surface area than either of Intel's stock coolers, with a much larger fan that can generate more airflow at lower noise levels. An aftermarket heatsink was necessary for our testing because the default Xeon cooler wouldn't actually install properly in the Gigabyte X48T-DQ6 motherboard we used to overclock the X3320. The Xeon cooler is an incredibly tight fit, and the Gigabyte board's socket backplate prevented it from flexing enough to set all the retention tabs. Despite its generous proportions, the Ninja installed without a hitch.