This info is taken from http://www.ocforums.com/showthread.php?t=306418
As you can see the 754 pin is Single channel, so at the time the article you mentioned was writen it was correct but now newer a64 chips have come out such as what you have.
Your cpu is Dual Channel capable, I have the same and I am runnign in dual channel.
Winchester (939)- Manufactured on a 90nm fabrication process, as opposed to the 130nm of the others. They range from speeds from 1.8GHz to 2.4 GHz, models starting with the 3000+ and ending with the 3800+. They dissipate 67W thermal watts of heat, and have a default voltage of 1.4v. Sports a 128-bit wide, dual channel memory controller, and supports unregistered memory. They are of D0 revision.
Clawhammer (939)- Found in the FX53(2.4 GHz), FX55(2.6GHz), and 4000+(2.4GHz). OPN code AS, revision CG. Can you tell Iâ€™m getting tired yet? Stock voltage of 1.5v, wattage of 89W. Sports a 128-bit wide, dual channel memory controller, and supports unregistered memory. The FX series have an unlocked range of multipliers, which the 4000+ lacks.
Newcastle (939)- Exactly the same as above, except only have 512k of L2 cache, and are found in the 3500+ and 3800+, OPN code AW, revision CG. Unlike the 940, the 939's have only one HyperTransport link, although for the end-user, this doesn't actually make any difference.
Clawhammer (754)- Come in both 512k and 1024k cache variants. Have a 64-bit wide, single channel DDR SDRAM controller. They come in speeds ranging from 1.6GHz to 2.4GHz, with PR ratings ranging from 2800+ to 3700+. There are two revisions of the A64. The first is the C0, which came in both 512k and 1024k flavors. The newer revision, the CG, comes in both, however the 512k parts are very rare. The last letter in the OPN code indicates itâ€™s revision; AP for C0â€™s, and AR for CGâ€™s. Both desktop and mobile parts are available on this core. Desktops and desktop replacement mobiles have a default voltage of 1.5v, and an approximate heat output of 81.9W. Mobiles have a default voltage of 1.4v, and approximate heat output of 62W.
Newcastle (754) - These are all 512k parts, and are about identical to the Clawhammers in every other respect. There are no C0 Newcastles. All Newcastles currently are CGâ€™s, as denoted by their OPN code of AX. These range in speeds from 1.6GHz to 2.4GHz, PR ratings from 2700+ to 3200+. The mobiles have a default core voltage of only 1.2v, and heat output of only 35W.
Sledgehammer (940)- Found the Opterons and the FX51, and some FX53â€™s. These all have 1024k of L2 cache, and have a 144-bit wide dual channel memory DDR SDRAM controller, supporting only registered memory. Speeds range from 1.4GHz to 2.4GHz. These are all based on a 940-pit socket package. The OPN codes that you will likely see are AG, which are B3â€™s, AK, which are C0â€™s, and ATâ€™s, which are CGâ€™s. They have stock voltages of 1.50v, and wattage ranges from 82.9W to 89W. The Sledgehammers have eight HyperTransport links for multi-way processing. These are factory enabled/disabled as appropriate, and cannot be modified.