Llano: What Is Inside?
Llano Is Fusion
In global terms Fusion concept implies that traditional processor cores and graphics cores merge on the hardware and software level. Therefore, any APU (accelerated processor unit) designed according to Fusion principles has a typical structure, which we have already discussed when we talked about Ontario and Zacate. Just like these energy-efficient APUs, Llano processors have computational x86 cores, a graphics core and a North Bridge. However, Llano and Zacate are similar only superficially.
Higher status of the new Llano processors that are positioned for mainstream systems called for faster APU components than those used in Zacate. Llano’s computational x86 cores are based on fully functional Stars microarchitecture and not on simplified Bobcat. There may be two, three or four computational cores like that inside an APU. Llano graphics core contains 320 or 400 stream processors, which is 4-5 times more than what Brazos processors have. And the built-in North Bridge supports high-speed dual-channel memory and has fully-fledged PCI Express interface for external graphics accelerators.
At the same time although Llano is a second processor in the Fusion family, the overall internal structure is pretty much the only principally new thing in it. In other words, the entire new APU is put together using old components with minimal innovations. If we were to characterize the newcomer without going too deep into details we would say that it were a combination of Athlon II X4 processor, Radeon HD 5570 graphics core and AMD 870 chipset put inside the same packaging onto a single semiconductor die. Of course, a description like that is very relative, because the new Llano does have minor innovations and unique technical implementations, but there is nothing principally new in this APU.
However, the mere fact that several very complex units were put together inside a single semiconductor die is already a serious step forward. It was only possible due to fine 32 nm process, which AMD’s production partner – GlobalFoundries – has finally fully mastered. So, AMD can now offer processors manufactured using the latest production process, which Intel has been using for about a year already.
Llano semiconductor die
The internal complexity of Llano semiconductor dies increased to 1.45 billion transistors. In this aspect new hybrid processors from AMD have slightly surpassed Intel’s Sandy Bridge. However, both - Llano and Sandy Bridge - have very similar die size: 228 vs. 216 mm2. It means that these processors should have comparable production cost, if we disregard the fact that Intel’s engineering team invested significantly more effort into their Sandy Bridge.
However, the similarity in semiconductor die characteristics between Llano and Sandy Bridge doesn’t really mean anything. These processors have dramatically different distribution of the “transistor budget”. While Intel product is just a CPU with an integrated graphics core, which occupies no more than 20% of the die, AMD Llano has its graphics core under much greater emphasis. Therefore, it takes up as much space on the processor die as four processor cores combined.
It is obviously the best illustration of what Llano can offer users. AMD bets on what they can currently do best: the graphics core. The processor cores have stepped back for the moment, that is why the success of the new processor will be closely connected with the overall success of the Fusion concept. If AMD really manages to move the major operational load to the GPU stream processors, then Llano will undoubtedly be superior to all existing competitors. However, it is still too early to talk about it: most software still works the old way, i.e. relying on traditional x86 processor cores.