Introduction

Unless you’ve been living under a rock for the past few months, chances are you know by now that AMD’s no longer on top in the CPU wars: in terms of overall performance, Intel’s new Core 2 CPU rocks AMD so hard it’s not even close right now, just as the Athlon 64 spanked the Pentium 4/Pentium D lines silly for the better part of the past three years. If you’re a hardware enthusiast that wants the fastest chip on the planet, Core 2 is without a doubt, the CPU for you.

But from here things get a little more difficult: what chipset should you pair your shiny new Core 2 CPU around? If you want to stick with a chipset from Intel you’ve basically got two choices -- 975X or P965 (Intel has other Core 2-compatible chipsets as well, but for varying reasons these really aren’t ideal for enthusiasts)

If you cared about ATI’s CrossFire graphics technology, up to a few weeks ago the choice was pretty simple: Intel’s 975X chipset. 975X is Intel’s high-end enthusiast level chipset, and was the only chipset to support CrossFire out of the gate at Core 2’s launch. But 975X is an older chipset, and is limited to officially supporting just DDR2-667 memory. In comparison, Intel’s newer P965 chipset officially supports both DDR2-667 and DDR2-800. DDR2-800 is capable of delivering 2.1GB/sec of additional memory bandwidth to the system. Peak bandwidth goes from 10.7GB/sec with DDR2-667 to 12.8GB/sec for DDR2-800.

Earlier this summer we ran some tests with a Core 2 Extreme and Core 2 Duo E6700 equipped with both DDR2-667 and DDR2-800 and found the faster memory provided an additional 2-4% in performance in games, while DDR2-800 shaved a few seconds off our DivX conversion and WME 9 tests in our media encoding testing.

Fortunately, most 975X motherboards offer a DDR2-800 setting inside their BIOS’, but officially this is considered overclocking by Intel/motherboard manufacturers, so you’ll get no support if it doesn’t work.

Radeon X1950 XTX CrossFire running on the P5B Deluxe

X1900 XTX CrossFire on the P5B Deluxe

Another downside to 975X is that it utilizes Intel’s older ICH7R South Bridge. ICH7 has been replaced the ICH8 South Bridge, which is used in the P965 chipset. ICH8 supports two additional Serial ATA drives (four in ICH7 versus six in ICH8) and two more USB ports (eight in ICH7 versus 10 in ICH8).

Arguably the biggest downside to 975X in comparison to P965 though is probably its cost. 975X motherboards typically sell for $50+ or more than equivalent P965 motherboards. When you consider the 975X chipset’s aforementioned deficiencies, and the fact that a lot of enthusiasts are finding that P965 overclocks a little further than 975X on average, a lot of power users would rather opt for a P965 motherboard instead of 975X, even though the 975X chipset was supposed to be tailored for the enthusiast. But then you lose the option of upgrading to CrossFire at some point in the future.

But what if there was a way you could add CrossFire support to the P965 chipset? You’d have the best of both worlds, as you’d have the superior features and lower price of P965 and CrossFire support, a feature that up until now has been exclusive to 975X.

Another shot of the CrossFire setup

With their latest driver release, Catalyst 6.9, this is precisely what ATI has enabled for CrossFire enthusiasts who want a P965 motherboard. But to get it all up and running, there are a few caveats you’ll have to keep in mind first. In this article we’re going to go over them, how well it all works, and finally, how it performs in comparison to 975X CrossFire. We also chat with ATI’s new Director of Marketing for Platform Technologies (read: CrossFire) Godfrey Cheng, and take a look at a very early beta copy of ATI’s upcoming Catalyst 6.10 driver which offers even more P965 CrossFire enhancements! Let’s get started…