AMD Phenom II X6: Thuban the Dragon Print E-mail
Written by Michael Schuette   
Apr 26, 2010 at 02:11 AM


PER ASPERA AT ASTRA or "to the stars through difficulties". The stars seem to be the motto embraced by AMD as of lately, we have Deneb, Propus, Heka and a few others and finally we have Thuban. And for the second part, there is no doubt either that AMD had difficulties enough in the recent past. Thuban is Arabic for Dragon which, given the role of Abu Dhabi's Advanced Technology Investment Co. in GlobalFoundries, a.k.a. AMD’s fab spin-off is a nice homage to the Middle East investor group that came forward at an extremely critical time. Thuban is also a star, of course, but we already knew that. In fact, Thuban‘s Bayer designation is alpha draconis, or in plain English, the lead star in the Draco (Dragon) constellation, which closes the loop to the Thuban name, moreover, in ancient times it was used as the north pole star.

So much for trivia. What we have at hand here is the desktop version of AMD’s Istanbul server processor, repackaged to fit into a 938-pin AM3 form factor and bringing 6 cores to the table. All that core goodness is complemented by 6 MB of shared, smart L3 cache and made out of 904 million transistors, even though this number is not officially confirmed by AMD. Of course, the number of transistors does require a certain footprint, which weighs in at a rather hefty 346 mm2.

TurboCORE

Beyond those raw technical bean-counting specs are a few real goodies that are infusing adrenaline into any AMD aficionado’s system. AMD is finally catching up with the turbo mode, that is, depending on the number of cores loaded, the top frequency changes. As we mentioned before in numerous articles, this type of adjustment is at the present time probably the best measure to cope with a heterogeneous software environment wherein single-threaded applications need all the frequency they can get while multi-threaded applications need to be confined within the thermal and power envelope available. All models that have TurboCORE enabled are designated by a T moniker. Currently, TurboCORE is only available in the 6 core offerings as shown in the table below.

ProcessorClock Speed L2 Cache L3 Cache TDPPrice
AMD Phenom II X6 1090T 3.2/3.6GHz3MB6MB125W$285
AMD Phenom II X6 1055T 2.8/3.3GHz3MB6MB125W$195
AMD Phenom II X4 965 BE (C2)3.4GHz2MB6MB140W$195
AMD Phenom II X4 965 BE (C3)3.4GHz2MB6MB125W$195
AMD Phenom II X4 955 BE3.2GHz 2MB6MB125W $175
AMD Phenom II X4 945 3.0GHz 2MB6MB125W$165
AMD Phenom II X4 925 2.8GHz 2MB6MB125W$145
AMD Phenom II X4 905e2.5GHz 2MB6MB65W$145
AMD Phenom II X3 720 BE2.8GHz 1.5MB6MB95W$145
AMD Phenom II X3 705 BE2.5GHz 1.5MB6MB65W$125
AMD Phenom II X2 550 BE3.1GHz 1MB6MB80W$105
AMD Athlon II X4 630 2.8GHz 2MBn/a95W$122
AMD Athlon II X4 620 2.6GHz 2MBn/a95W$99
AMD Athlon II X3 435 2.9GHz 1.5MBn/a95W$87
AMD Athlon II X3 425 2.7GHz 1.5MBn/a95W$76
AMD Athlon II X2 250 3.0GHz 2MBn/a65W$69
AMD Athlon II X2 245 2.9GHz 2MBn/a65W$64
AMD Athlon II X2 240 2.8GHz 2MBn/a65W$60
AMD Athlon II X4 605e2.3GHz 2MBn/a45W$143
AMD Athlon II X4 600e2.2GHz 2MBn/a 45W$133
AMD Athlon II X3 405e2.3GHz 1.5MBn/a45W$102
AMD Athlon II X3 400e2.2GHz 1.5MBn/a45W$97
AMD Athlon II X2 240e2.8GHz 2MBn/a 45W$77
AMD Athlon II X2 235e2.7GHz 2MBn/a 45W$69

Energy-efficient models are hi-lighted in green

In short, AMD’s strategy is to have 5 p-states, that is frequency states of the CPU that are defined in hardware. The individual frequencies corresponding to the different p-states are model-dependent as before, however, the novelty in the case of Thuban is that the OS does a p-state translation. That is AMD’s TurboCORE technology adds an offset to the hardware p-states, resulting in the OS to register hardware p-state 1 as P-state 0. In other words, the maximum frequency is not recognized by the OS as a standard p-state but rather as a Turbo state. What this means in simple terms is that for example the Phenom II X6 1090T is configured in hardware as a 3.6 GHz CPU but the Turbo-Boost technology culls it at 3.2 GHz as soon as more than 3 cores are loaded.

The limiting factor for the core frequency is the TDP or actually an assumed TDP that is managed through the NB-interlock to ensure that under all circumstances the CPU remains within the specified TDP. Bear in mind that Windows Task Manager will most likely show all cores being busy since in most cases, the threads are not hard-affinitized but move from one core to another for reasons of thermal and power distribution. Another thing to bear in mind is that AMD’s TurboCORE technology at this point only works with Microsoft operating systems.

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Last Updated ( May 05, 2010 at 02:59 PM )
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