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Matchups to watch
Before we move on to our test results, we should pause to consider several of the key matchups. The most obvious of those is the battle at 3.2GHz, where we pit the Core i7-965 Extreme against the fastest single-socket Core 2 processor, the Core 2 Extreme QX9770. This is, more or less, the clock-for-clock matchup between old and new generations that you'll want to watch. Only it's sort of bogus, since Turbo mode means the Core i7-965 Extreme typically runs at 3.33GHz or more.

Also contending at 3.2GHz: a dual-socket rig, the "Skulltrail" system with repurposed Xeons branded as Core 2 Extreme QX9775 processors. We threw this one in for fun, to see how this "ultimate" and "extreme" system would match up against the fastest Core i7. Of course, it's not a fair fight, but it sure is a fun one.

One of the most intriguing matchups may be the Core i7 versus itself. We've tested the 965 Extreme with and without Hyper-Threading enabled, throughout our test suite, to see what different this feature makes. Watch for the "No HT" results to see what happens when Hyper-Threading is disabled.

Then there's the face-off of the value quad cores, all of which have, at one time, occupied the basic price point at which the Core i7-920 now debuts. The Core 2 Quad Q6600 is a first-generation 65nm Core 2 processor and a long-time favorite here at TR. The 45nm Core 2 Quad Q9300 essentially supplanted the Q6600 and found its way into several of our system guide recommended configs during its time. I'm intrigued to see how the Core i7-920's performance and value proposition matches up to these two economical quad-core CPUs.

Another quad contender with a nice, low price is the Phenom X4 9950. It's also AMD's current top-of-the line processor, so we've of course included it. However, AMD's pricing very much reflects its products' limited performance, so there's no direct competition right now between even the Core i7-920 and anything AMD has to offer.

Also in the mix for reference are a couple of higher frequency dual-core processors: the Core 2 Duo E8600, which runs at 3.33GHz and promises to perform very well in lightly threaded applications, and the Athlon 64 X2 6400+. At 3.2GHz, the X2 6400+ is AMD's highest frequency desktop processor, and it may even upstage the Phenom in single- or dual-threaded apps. These days, though, AMD has chosen to fight Intel's high-frequency dual cores with its triple core Phenom X3 8750, so we've included it, as well.

Test notes
We didn't become entirely aware of the various flexible uncore clock options for Nehalem until the eleventh hour, and as a result, we've only just discovered a problem with one of our test setups. You will see in the table below and throughout the review scores for a "Core i7-940" processor that is really just a Core i7-965 Extreme processor underclocked to the 2.93GHz core clock of the 940 model. Generally, simulating a speed grade of a chip like this isn't a big problem, at least for performance testing if not power consumption. However, it turns out that, in following the guide Intel offered to us for simulating a 940 with a 965, we (and they) missed a key variable: the "uncore" clock. Ours was running at 3.2 GHz when we simulated the 940, when the proper clock speed is 2.13 GHz. That discrepancy potentially made both the memory controller and the L3 cache quicker than they would probably be in the actual product. We've decided to leave the numbers for the 940 in the review, but please realize that they may overstate its performance somewhat. We will try to follow up with more exact numbers in a future article or update.

Special thanks to Corsair for equipping us with all-new memory we used in testing. The most impressive DIMMs they supplied us were part of a special Core i7-tailored three-module kit, pictured above. These puppies ran happily at their rated 8-8-8-24 timings, with a 1T command rate, at 1600 MHz and only 1.65V. The Core i7 memory controller apparently may not deal well with higher voltages, but we found they weren't necessary with these DIMMs.

Also, thanks to Asus for bringing our Phenom testbed up to date with this M3A79-T Deluxe mobo. We sought this one out because it has a 790FX north bridge combined with AMD's new SB750 south bridge. Oh, yeah, and check out that CPU cooler, which I was too lazy to remove for the picture (and doing so would have decreased its awesomeness). Don't put your finger in the fan, folks.

Our testing methods
As ever, we did our best to deliver clean benchmark numbers. Tests were run at least three times, and the results were averaged.

Our test systems were configured like so:

Processor Core 2 Quad Q6600 2.4 GHz Core 2 Duo E8600 3.33 GHz
Core 2 Quad Q9300 2.5 GHz
Core 2 Extreme QX9770 3.2 GHz Dual Core 2 Extreme QX9775 3.2 GHz Core i7-920 2.66 GHz
Core i7-940 2.93 GHz
Core i7-965 Extreme 3.2 GHz Athlon 64 X2 6400+ 3.2 GHz Phenom X3 8750 2.4 GHz
Phenom X4 9950
Black 2.6 GHz
System bus 1066 MT/s
(266 MHz)
1333 MT/s
(333 MHz)
1600 MT/s
(400 MHz)
1600 MT/s
(400 MHz)
QPI 4.8 GT/s
(2.4 GHz)
QPI 6.4 GT/s
(3.2 GHz)
HT 2.0 GT/s
(1.0 GHz)
HT 3.6 GT/s (1.8 GHz)
HT 4.0 GT/s (2.0 GHz)
Motherboard Asus P5E3 Premium Asus P5E3 Premium Asus P5E3 Premium Intel D5400XS Intel DX58SO Intel DX58SO Asus M3A79-T Deluxe Asus M3A79-T Deluxe
BIOS revision 0605 0605 0605 XS54010J.86A.1149.
2008.0825.2339
SOX5810J.86A.2260.
2008.0918.1758
SOX5810J.86A.2260.
2008.0918.1758
0403 0403
North bridge X48 Express MCH X48 Express MCH X48 Express MCH 5400 MCH X58 IOH X58 IOH 790FX 790FX
South bridge ICH9R ICH9R ICH9R 6321ESB ICH ICH10R ICH10R SB750 SB750
Chipset drivers INF Update 9.0.0.1008
Matrix Storage Manager 8.5.0.1032
INF Update 9.0.0.1008
Matrix Storage Manager 8.5.0.1032
INF Update 9.0.0.1008
Matrix Storage Manager 8.5.0.1032
INF Update 9.0.0.1008
Matrix Storage Manager 8.5.0.1032
INF update 9.1.0.1007
Matrix Storage Manager 8.5.0.1032
INF update 9.1.0.1007
Matrix Storage Manager 8.5.0.1032
AHCI controller 3.1.1540.61 AHCI controller 3.1.1540.61
Memory size 4GB (2 DIMMs) 4GB (2 DIMMs) 4GB (2 DIMMs) 4GB (2 DIMMs) 6GB (3 DIMMs) 6GB (3 DIMMs) 4GB (2 DIMMs) 4GB (2 DIMMs)
Memory type Corsair TW3X4G1800C8DF
DDR3 SDRAM
Corsair TW3X4G1800C8DF
DDR3 SDRAM
Corsair TW3X4G1800C8DF
DDR3 SDRAM
Micron ECC DDR2-800
FB-DIMM
Corsair TR3X6G1600C8D
DDR3 SDRAM
Corsair TR3X6G1600C8D
DDR3 SDRAM
Corsair TWIN4X4096-8500C5DF
DDR2 SDRAM 
Corsair TWIN4X4096-8500C5DF
DDR2 SDRAM
Memory speed (Effective) 1066 MHz 1333 MHz 1600 MHz 800 MHz 1066 MHz 1600 MHz 800 MHz 1066 MHz
CAS latency (CL) 7 8 8 5 7 8 4 5
RAS to CAS delay (tRCD) 7 8 8 5 7 8 4 5
RAS precharge (tRP) 7 8 8 5 7 8 4 5
Cycle time (tRAS) 20 20 24 18 20 24 12 15
Command rate 2T 2T 2T 2T 2T 1T 2T 2T
Audio Integrated ICH9R/AD1988B
with SoundMAX 6.10.2.6480 drivers
Integrated ICH9R/AD1988B
with SoundMAX 6.10.2.6480 drivers
Integrated ICH9R/AD1988B
with SoundMAX 6.10.2.6480 drivers
Integrated 6321ESB/STAC9274D5
with SigmaTel 6.10.5713.7 drivers
Integrated ICH10R/ALC889
with Realtek 6.0.1.5704 drivers
Integrated ICH10R/ALC889
with Realtek 6.0.1.5704 drivers
Integrated SB750/AD2000B
with SoundMAX 6.10.2.6480 drivers
Integrated SB750/AD2000B
with SoundMAX 6.10.2.6480 drivers
Hard drive WD Caviar SE16 320GB SATA
Graphics Radeon HD 4870 512MB PCIe with Catalyst 8.55.4-081009a-070794E-ATI drivers
OS Windows Vista Ultimate x64 Edition
OS updates Service Pack 1, DirectX redist update August 2008

Thanks to Corsair for providing us with memory for our testing. Their products and support are far and away superior to generic, no-name memory.

Our single-socket test systems were powered by OCZ GameXStream 700W power supply units. The dual-socket system was powered by a PC Power & Cooling Turbo-Cool 1KW-SR power supply. Thanks to OCZ for providing these units for our use in testing.

Also, the folks at NCIXUS.com hooked us up with a nice deal on the WD Caviar SE16 drives used in our test rigs. NCIX now sells to U.S. customers, so check them out.

The test systems' Windows desktops were set at 1600x1200 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled.

We used the following versions of our test applications:

The tests and methods we employ are usually publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.