A very smart man once told me that absolute performance doesn’t matter, it’s performance at a given price point that makes a product successful. While AMD hasn’t held the absolute performance crown for several years now, that doesn’t mean the company’s products haven’t been successful.

During the days of the original Phenom, AMD started the trend of offering more cores than Intel at a given price point. Intel had the Core 2 Duo, AMD responded with the triple core Phenom X3. As AMD’s products got more competitive, the more-for-less approach didn’t change. Today AMD will sell you three or four cores for the price of two from Intel.

In some situations, this works to AMD’s benefit. The Athlon II X3 and X4 deliver better performance in highly threaded applications than the Intel alternatives. While Intel has better performance per clock, you can’t argue with more cores/threads for applications that can use them.

When Intel announced its first 6-core desktop processor, the Core i7 980X at $999, we knew a cheaper AMD alternative was coming. Today we get that alternative, this is the Phenom II X6 based on AMD’s new Thuban core:

It’s still a 45nm chip but thanks to architecture and process tweaks, the new Phenom II X6 still fits in the same power envelope as last year’s Phenom II X4 processors: 125W.

Update: AMD tells us that it gave us the wrong pricing on the 1090T. The part sells for $295, not $285, in 1000 unit quantities.

CPU Specification Comparison Processor Clock Speed Max Turbo L2 Cache L3 Cache TDP Price AMD Phenom II X6 1090T 3.2GHz 3.6GHz 3MB 6MB 125W $295 AMD Phenom II X6 1055T 2.8GHz 3.3GHz 3MB 6MB 125W $199 AMD Phenom II X4 965 BE 3.4GHz N/A 2MB 6MB 125W/140W $185 AMD Phenom II X4 955 BE 3.2GHz N/A 2MB 6MB 125W $165 AMD Phenom II X4 945 3.0GHz N/A 2MB 6MB 95W $155 AMD Phenom II X4 925 2.8GHz N/A 2MB 6MB 95W $145

You also don’t give up much clock speed. The fastest Phenom II X6 runs at 3.2GHz, just 200MHz shy of the fastest X4.

When Intel added two cores to Nehalem it also increased the L3 cache of the chip by 50%. The Phenom II X6 does no such thing. The 6 cores have to share the same 6MB L3 cache as the quad-core version.



The Phenom II X6 die. Monolithic, hexa-core

There’s also the issue of memory bandwidth. Intel’s Core i7 980X is paired with a triple channel DDR3 memory controller, more than enough for four cores under normal use and enough for a six core beast. In order to maintain backwards compatibility, the Phenom II X6 is still limited to the same dual channel memory controller as its quad-core predecessor.

CPU Specification Comparison CPU Codename Manufacturing Process Cores Transistor Count Die Size AMD Phenom II X6 1090T Thuban 45nm 6 904M 346mm2 AMD Phenom II X4 965 Deneb 45nm 4 758M 258mm2 Intel Core i7 980X Gulftown 32nm 6 1.17B 240mm2 Intel Core i7 975 Bloomfield 45nm 4 731M 263mm2 Intel Core i7 870 Lynnfield 45nm 4 774M 296mm2 Intel Core i5 670 Clarkdale 32nm 2 384M 81mm2 AMD Phenom II X4 965 Deneb 45nm 4 758M 258mm2

The limitations are nitpicks in the grand scheme of things. While the 980X retails for $999, AMD’s most expensive 6-core processor will only set you back $285 and you can use them in all existing AM2+ and AM3 motherboards with a BIOS update. You're getting nearly 1 billion transistors for $200 - $300. Like I said earlier, it’s not about absolute performance, but performance at a given price point.

AMD 2010 Roadmap CPU Clock Speed Max Turbo (<= 3 cores) L3 Cache TDP Release AMD Phenom II X6 1090T 3.2GHz 3.6GHz 6MB 125W Q2 AMD Phenom II X6 1075T 3.0GHz 3.5GHz 6MB 125W Q3 AMD Phenom II X6 1055T 2.8GHz 3.3GHz 6MB 125W/95W Q2 AMD Phenom II X6 1035T 2.6GHz 3.1GHz 6MB 95W Q2 AMD Phenom II X4 960T 3.0GHz 3.4GHz 6MB 95W Q2

We'll soon see more flavors of the Phenom II X6 as well as a quad-core derivative with 2 of these cores disabled. As a result, motherboard manufacturers are already talking about Phenom II X4 to X6 unlocking tools.

The new Phenom II X6 processors are aimed squarely at Intel’s 45nm Lynnfield CPUs. Both based on a 45nm process, AMD simply offers you more cores for roughly the same price. Instead of a quad-core Core i7 860, AMD will sell you a six-core 1090T. Oh and the T stands for AMD’s Turbo Core technology.