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The Phenom II X6 and the competition
We could be comparing AMD's two Phenom II X6 processors to the Core i7-980X Extreme. We could tell you the AMD chips are based on older process technology and have larger dies yet slightly lower TDP ratings. We could say the 980X and the fastest Phenom II X6 have almost the same base and "turbo" clock speeds, although the Intel part has double the L3 cache, one more memory channel, and twice the thread count. We could go on.

Contrasting these two chips would only have an academic interest, however, because AMD's pricing dictates an entirely different comparison. You see, instead of going toe-to-toe with the 980X at $999, AMD has opted to offer the fastest of its two Phenom II X6 processors for $295. The slower one has an even lower bulk price: $199. As a result, we'll largely be comparing the newcomers to Intel's quad-core, 45-nm Core i5 and i7 products.

Before we do that, we should take a moment to introduce fully the two Phenom II X6 processors AMD has released today:

Model Cores Threads Base core
clock speed
Peak Turbo
clock speed
L3 cache
size
Memory
channels
TDP Price
Phenom II X6 1055T 6 6 2.8 GHz 3.3 GHz 6 MB 2 125W $199
Phenom II X6 1090T
Black Edition
6 6 3.2 GHz 3.6 GHz 6 MB 2 125W $295

Update 04/28: AMD originally told us the Phenom II X6 1090T would have a $285 price tag. Today, the company sent us an e-mail saying the 1090T is in fact priced at $295. We've updated this article—including our value section on page 15—to reflect the change.

These CPUs cap off the Phenom II family, whose quad-core models are listed below:

Model Cores Threads Base core
clock speed
Peak Turbo
clock speed
L3 cache
size
Memory
channels
TDP Price
Phenom II X4 905e 4 4 2.5 GHz N/A 6 MB 2 65W $165
Phenom II X4 910e 4 4 2.6 GHz N/A 6 MB 2 65W $175
Phenom II X4 925 4 4 2.8 GHz N/A 6 MB 2 95W $145
Phenom II X4 945 4 4 3.0 GHz N/A 6 MB 2 95W $155
Phenom II X4 955
Black Edition
4 4 3.2 GHz N/A 6 MB 2 125W $165
Phenom II X4 965
Black Edition
4 4 3.4 GHz N/A 6 MB 2 140W $185

As you can see, the Phenom II X6 sets a new high-water mark for both pricing and specifications in AMD's desktop product line. Remember what we said about power envelopes earlier? The Phenom II X6 1090T can run six cores at the same speed as the quad-core Phenom II X4 955 Black Edition within the same 125W power envelope. When Turbo kicks in and pushes three of its cores to 3.6GHz, the 1090T should also deliver better performance in lightly multithreaded applications than the 965 Black Edition, which maxes out at 3.4GHz regardless of the load.

AMD has positioned both Phenom II X6 variants smack-dab in quad-core Core i5 and i7 territory, although once again, it doesn't pretend to tackle the high end. Intel's "Extreme" processors will probably remain unchallenged until at least the next AMD CPU generation.

Model Cores Threads Base core
clock speed
Peak Turbo
clock speed
L3 cache
size
Memory
channels
TDP Price
Core i5-750 4 4 2.66 GHz 3.20 GHz 8 MB 2 95W $196
Core i7-860 4 8 2.80 GHz 3.46 GHz 8 MB 2 95W $284
Core i7-870 4 8 2.93 GHz 3.60 GHz 8 MB 2 95W $562
Core i7-920 4 8 2.66 GHz 2.93 GHz 8 MB 3 130W $284
Core i7-930 4 8 2.80 GHz 3.06 GHz 8 MB 3 130W $294
Core i7-960 4 8 3.20 GHz 3.46 GHz 8 MB 3 130W $562
Core i7-975 Extreme 4 8 3.33 GHz 3.60 GHz 8 MB 3 130W $999
Core i7-980X Extreme 6 12 3.33 GHz 3.60 GHz 12 MB 3 130W $999

In terms of official, bulk pricing numbers, it would appear AMD has priced the Phenom II X6 1055T opposite the Core i5-750 and the 1090T against a pair of Intel offerings: the Core i7-860 and a relative newcomer, the Core i7-930, which essentially replaces the Core i7-920. Those are bold moves. The Core i5-750 in particular has displayed a unique mix of performance, power efficiency, and value, faring exceptionally well in our past value comparisons.

We have tested most of these processors in the following pages. One painful exception is the Core i7-860, which is unfortunately absent. We can still compare the Phenom II X6 1090T to the Core i7-930, and you might also want to keep in mind that the Core i7-860's performance and power draw would likely be just a little lower than the i7-870's.

The 890FX chipset and our motherboard
AMD's new Phenoms are joining us together with a new chipset, the 890FX, which constitutes the new high end for AMD motherboards.

Just like the 790FX before it, the 890FX brings us generous amounts of connectivity options and oodles of PCI Express lanes. Both chipsets actually use pretty much the same north bridge: a slab of 65-nm silicon with 42 lanes of second-generation PCI Express connectivity hooked up to the processor via a 4 GT/s HyperTransport 3.0 link.

AMD pairs this north bridge with its new SB850 south bridge, which we recently reviewed as part of the 890GX chipset. The SB850 delivers six Serial ATA 6Gbps ports (all backward-compatible with previous versions of the standard, of course), 14 USB 2.0 ports, integrated Gigabit Ethernet, and 32-bit PCI connectivity. What differentiates the 890FX from the 890GX is the north-bridge component, then, which lacks integrated graphics but packs considerably more PCIe lanes than in the 890GX.

We'll talk more about our testing setup shortly, but in case you're wondering, we did test Thuban using an 890FX mobo—the MSI 890FXA-GD70, to be precise. As the image above attests, this board is part of a new wave of high-end Socket AM3 motherboards meant to match the Phenom II X6's more upscale pedigree.