Intel Core i7-980X Extreme Edition Review

Testing

To determine how much difference the i7-980X's two extra cores and additional cache make to performance, we benchmarked it against its Extreme Edition predecessor, the i7-975, and the far more reasonably priced i7-930, also launched this month.

Although we did try the i7-980X in several different LGA1366 motherboards, Asus seems to be much more geared up to support the new CPU, with various BETA BIOSes being released over the last six months.

As a result, all three CPUs were tested with the same Asus P6TD Deluxe motherboard using the latest 0404 BIOS, specially written to support the i7-980X.

Even though it's not a direct competitor we've also included the benchmark results for AMDs fastest desktop CPU, the Phenom II X4 965 Black Edition, so you can see just how behind Intel AMD now is. This CPU was tested in a MSI 790FX-GD70 motherboard with 4GB (2 x 2GB) of Corsair XMS3-1600 memory (1,600MHz, CL9 DDR3).

Test Setup

Software

Here is a list of the applications we've used for our testing - most of them are available free for public consumption, although some are popular professional software applications.

• Crysis v1.21
  
• X3: Terran Conflict rolling demo v1.2.0.0
  
• WPrime v2.00
  
• Custom PC Benchmarks v2007.235
  
• Maxon Cinebench 10 (x64)

We've used Windows 7 Home Premium 64-bit, as this is the most flexible and reliable 64-bit OS for testing the applications above.

Hardware

• ATI Radeon HD 5870 graphics card (Catalyst 10.1 WHQL)
  
• 1TB Seagate Barracuda 7200.12 hard disk
  
• PC Power & Cooling 750W PSU
  
• Asus P6TD Deluxe motherboard
  
• 6GB (3 x 2GB) OCZ Blade PC3-1600 memory (1,600MHz, CL7 DDR3)
  
• Titan Fenrir TTC-NK85TZ CPU cooler

Testing and Overclocking

While the i7-980X's stock-speed performance results are interesting, Extreme Editions are made for overclocking. For example, unlike a standard Core i7 CPU, the i7-980X and i7-975 both have an unlocked CPU multiplier, so with the right cooling, they can be overclocked much higher.

However, while the i7-975 was merely a very good overclocker - it only overclocked by 200-300MHz more than a standard Core i7 - the i7-980X has an ace up its sleeve: its 32nm transistors. These smaller, faster transistors allowed us not only to overclock the i7-980X to a much higher frequency than the i7-975, but also to use less voltage to do so. The lower the voltage required for an overclock the better, as more voltage means more power to dissipate from the CPU (in the form of heat), and more stress on the motherboard's VRMs.

With the Titan Fenrir air cooler, the i7-975 topped out at 4.27GHz with a CPU multiplier of 24x, QPI of 178MHz and a vcore of 1.45V. While this is a good overclock, and boosted the overall Media Benchmarks score from 1,896 to 2,326, the i7-980X overclocked to 4.4GHz with a CPU multiplier of 22x, QPI of 200MHz and a vcore of just 1.38125V. This monster overclock raised the score considerably from 2,002 to 2,581. At 4.4GHz, the i7-980X was also much faster than the pair of W5580s in Cinebench, scoring 35,004 compared to 28,980.

As the i7-980X proved to be such a sterling overclocker with air cooling, we decided that it would be criminal not to give it a shot with water cooling. Using a Swiftech Apogee XT waterblock and Blastflow quad 120mm radiator, we were able to push the i7-980X to 4.72GHz by using a CPU multiplier of 23x, QPI of 205MHz and a vcore of 1.45V. This is the same vcore that the i7-975 needed to hit just 4.27GHz, which is nearly half a gigahertz slower. At 4.72GHz, the i7-980X returned a ludicrously high overall score of 2,715 in our Media Benchmarks and 36,222 in Cinebench.

While Crysis refused to run faster (the Radeon HD 5870 graphics card appears to be the bottleneck in this), the geometry-heavy X3 ran faster with the i7-980X at 4.72GHz. Clearly, the overclocking wizards at Intel had a lot of fun making the i7-980X, and as a result, it's an unparalleled overclocker.

The highest stable overclock for each CPU and the settings we used is collated in a handy Overclocking Reference table (see below).