Thuban: Istanbul for Socket AM3
Six-core AMD processor is in fact no innovation. The company has already been shipping their six-core CPUs also known as Istanbul to the server and workstation market. However, it has never prevented anyone interested from using these processors in desktops, which we have already discussed in detail here. Now CPUs similar to Istanbul have finally officially arrived into the desktop segment. They are also known under Thuban codename and they will be selling as Phenom II X6.
It is quite obvious why AMD decided to release a six-core desktop processor only now. Now, it is not because of the introduction of the new manufacturing process. The thing is that the 45 nm technological process this company uses for manufacturing of their contemporary processors has matured enough to ensure that the production cost of relatively large six-core semiconductor dies allows the CPUs based on them to be priced acceptably for individual end-users. Moreover, keeping in mind that the current AMD processors with Stars (K10.5) microarchitecture can’t compete against Intel high-end solutions in performance, they are going to sell Phenom II X6 at very attractive prices of $200-$300.
Nevertheless, Phenom II X6 processors are based on a completely fully-functional monolithic semiconductor die measuring 346 mm2 in size, which is exactly the same as server Opteron 2400 and 8400 processors.
Of course, the number of HyperTransport busses in six-core Thuban processor has been cut down to one and the memory controller has been modified to support unbuffered memory DIMMs, but these are minor and insignificant changes. At the same time I can say that Thuban is a direct successor to quad-core Deneb processors that simply acquired two additional cores. All shared units in Thuban, such as the memory controller or the HyperTransport bus are exactly the same as those in quad-core Phenom II X4 processors. Even the shared L3 cache memory remained the same: 6 MB.
So, no wonder that the new six-core Phenom II X6 processors are fully compatible with existing Socket AM3 and Socket AM2+ mainboards. AMD keeps sticking to their platform continuity principles. The only thing you might need to ensure that new processors work properly in the existing mainboards is a BIOS update.
At the same time AMD prepared a much unexpected surprise for their loyal fans. Phenom II X6 clock frequencies will reach 3.2 GHz, which is significantly higher than the frequency of top server processors with six computational cores. We owe this to AMD’s production partner, Globafoundries Company, as they mastered the use of a new material with low-k dielectric between the conductor layers. This produced six-core processors with relatively high clock frequency, but still the same 125 W TDP.
Moreover, AMD suggested one more enhancement that makes Phenom II X6 even more attractive for general-purpose applications: Turbo CORE technology. Let’s take a real close look at it now.