AMD Athlon II X2
Judging by the specs, Phenom II X2 500 series processors should be a very good offer for the sub-$100 price range. However, it is fairly expensive for AMD to make these CPUs. Their die size is comparable to the die of flagship Intel Core i7 solutions, which means that Phenom II X2 500 production cost is relatively high. Therefore, it is obvious that Phenom II X2 500 series appeared only because AMD didn’t want to waste defective quad-core Deneb dies. They are very unlikely to use fully-functional dies for these dual-core processors. And it means that AMD doesn’t have the opportunity to supply sufficient volume of Phenom II X2 500 CPUs to the market and they will hardly save the situation with AMD dual-core processors in the mainstream segment.
Therefore, it is not surprising that besides Phenom II X2, AMD is also launching one more CPU – Athlon II X2. Although this processor has similar specifications to Phenom, it is based on a cheaper Regor core. The main differences between Deneb and Regor are right there in front of you: this semiconductor die has only a pair of computational cores and no L3 cache at all, which makes it smaller in size and cheaper to manufacture. From the architectural prospective, Athlon II X2 dies are hardly any different from the Phenom II X2 processors: they use absolutely identical K10 (Stars) microarchitecture. The only modification introduced by AMD engineers is a larger L2 cache of each individual core: its size has been increased from 512KB to 1024KB, which should somehow make up for the absence of any L3 cache memory in Regor.
As a result, Regor die measures 117.5sq.mm, which makes less than half the size of Deneb die. And it is about the same as the die size of dual-core Intel processors from Core 2 Duo E8000 family also manufactured with 45nm process. However, it is important to remember that Intel processors are much more “complex”: they consist of about 410 million transistors, while Regor core has only 234 million of them. That is why contemporary dual-core Intel processors on Wolfdale core have a 6MB L2 cache, while Athlon II X2 CPUs with the die of the same size are only equipped with a total of 2MB L2 cache memory.
The semiconductor Regor die specifically designed by AMD engineers also allowed lowering the heat dissipation and power consumption levels for dual-core AMD processors. Dual-core Phenom II X2 500 based on Deneb core dissipates about 80W of heat, while Athlon II X2 processors on Regor core have 65W TDP. Therefore AMD hopes that the introduction of 45nm process for dual-core CPU manufacturing will allow their new solutions to compete against Intel not only in performance but also in power-efficiency.
At the same time AMD wants to present Athlon II X2 family as a simpler and cheaper solution than Phenom II X2 500. That is why CPUs in this family will work at lower clock frequencies and will also sell for less: for example, the top Athlon II X2 250 model is officially priced at $87, which is $15 less than what Phenom II X2 550 is selling for. However, when you compare the specifications of these two processors side by side, you can’t claim with all certainty that Athlon II X2 yields to Phenom II X2 500 in anything at all. To illustrate this point let’s check out the specifications of the two new dual-core AMD processors side by side. Here they are – Phenom II X2 500 series and Athlon II X2 200 series CPUs:
In our opinion both AMD solutions belong to the same class of dual-core processors. And the fact that both of them, Athlon II X2 as well as Phenom II X2, are compatible with the new Socket AM3 platform helps promote the new platform in the market. And this platform is going to get even more and more popular, especially since DDR3 SDRAM prices have just dropped and inexpensive Socket AM3 mainboards based on AMD770 chipset start selling freely.
For our performance tests we are going to use a top product in the Athlon II X2 family – 3GHz Athlon II X2 250. You can see the specifications of this particular processor on a CPU-Z screenshot below:
The diagnostic utility we are using at this time is not yet very well familiar with the new Regor CPU core. Nevertheless, it does display all parameters correctly. It is here that you can already notice that Athlon II X2 processor stepping is different from that of Callisto core used in Phenom II X2, thus stressing different origin of the two.