The History Of AMD CPUs

AMD K10: Fusion/Llano

AMD's Fusion project came to fruition in July 2011, when the company released its first APUs, code-named "Llano." The design combined a large number of AMD's Radeon Stream Processors based on the TeraScale 2 architecture with the company's K10 CPU cores. The underlying concept was similar to AMD's Geode line, which hadn't been updated in years. But where the Geode was designed as a low-power/performance solution, Llano was meant to be a higher-performance product.

It was never meant to compete in the high-end, but the idea was to create a SKU that could give reasonable CPU and graphics performance all in one. Llano suffered from a lack of L3 cache, and the iGPU was far too slow to keep most gamers happy, but for casual gamers that didn't mind lower graphics settings, it performed well enough.

AMD Llano

AMD Bobcat

To be more competitive with Intel's Atom and ARM's low-power microprocessors, AMD introduced its Bobcat architecture in 2011. Since Bobcat was designed to be efficient, it ran at fairly low clock speeds; the highest-performing model reached 1.75 GHz. Bobcat is technically an APU, and it contains an iGPU with 80 Stream Processors based on the TeraScale 2 architecture. The iGPU is clocked rather conservatively as well in order to keep power consumption low.

AMD Bobcat

AMD Bulldozer: Zambezi

In October 2011, AMD introduced the successor to its K10 architecture, code-named "Bulldozer." With Bulldozer, AMD attempted to use high core count and clock speed to outperform Intel's recently-released Sandy Bridge. The cost of this clock rate-focused design, however, was a marked drop in IPC compared to the K10 architecture, and the design has been plagued with problems. The first Bulldozer chip, code-named Zambezi, was not able to cleanly out-perform Thuban Phenom II X6 CPUs, let alone beat Sandy Bridge. Part of the problem came from the use of a Multi-Core Module (MCM) that contains two integer cores and one FPU. As the two integer execution units have to share the FPU, this can lead to stalls in the pipeline.

The design has also been criticized for being power-hungry and running too hot, though that stems from direct comparisons between Bulldozer and Sandy Bridge.

AMD Bulldozer Zambezi

AMD Piledriver: Trinity And Richland

A year after Bulldozer debuted, AMD released a revised architecture known as Piledriver. Piledriver was initially released with Trinity, the company's second-gen APU. It saw clock speed increase by about 10 percent, and that, in conjunction with architectural enhancements, pushed performance up by roughly 15 percent without increasing power consumption.

On the iGPU side, Trinity moved to the TeraScale 3 architecture used inside of AMD's Radeon HD 6900-series GPUs. This helped to increase graphics performance over Llano.

Richland, in turn, was a slightly improved Piledriver part. It performed just slightly better than Trinity due to higher clock speeds. It also managed to reduce power consumption and heat somewhat. The performance gap between mobile Trinity APUs and mobile Richland APUs was greater than on the desktop, owing to the improved thermals and power consumption.

AMD Trinity And Richland APUs

AMD Piledriver: Vishera

AMD also applied its Piledriver architecture to the FX family, displacing Zambezi in favor of Vishera.

AMD Bulldozer Vishera

AMD Steamroller: A GCN APU

In 2014, AMD updated its APU line again with the new Steamroller architecture. AMD shifted to a new 28nm process that favored chip density over clock speeds in order to be more compatible with its graphics technology. The CPU demonstrated a reasonable increase in IPC over its predecessor, thanks in part to a larger L1 cache and additional internal registers. It wasn't able to hit the same clock speeds as Richland though, so overall performance didn't increase much.

The graphics side of the APU improved drastically, however, owing to the new transistor technology, an increase in shader count, and a move to AMD's GCN GPU architecture. The APU featured a number of other enhancements, such as being the first HSA-compatible APU, the addition of AMD's TrueAudio DSP technology and support for PCIe 3.0.

The first Steamroller APUs use a configuration known as Kaveri. The APU line was later refreshed with Godavari, which benefits mostly from higher clock speeds.

AMD Jaguar

AMD introduced its Jaguar architecture in 2014 to replace the aging Bobcat core. Jaguar increased the CPU core count to four and moved to a faster GCN-based graphics processor with 128 shaders. IPC shot up by roughly 15 percent as well, alongside a boost in clock speed. Overall, Jaguar is significantly faster than Bobcat in every way.

The Jaguar architecture in also used inside of the Xbox One and Playstation 4. The models inside of these game consoles have significantly higher core counts on both the CPU and iGPU, however, and Jaguar-based products available in other devices are considerably slower.

AMD Jaguar

Excavator: The End Of Bulldozer

The last architecture that AMD plans to produce based on Bulldozer is known as Excavator, which is used inside of AMD Carrizo-based APUs. Relatively few of these products have been released thus far, so we can't be sure what the clock speed limit will be on these parts. Carrizo is designed to have significantly higher transistor density (than prior Bulldozer-based processors), which helps to reduce the die area and lower power consumption. AMD reworked the cache inside of Excavator, too.

The processor has less L2 cache, but twice as much L1 cache when compared to Steamroller. Because the L1 cache is several times faster than the L2 cache, this helps to boost IPC performance. The branch prediction target buffer was increased by 50 percent as well, to 768 KB, which further helps to improve performance. The graphics processor also gained 512 KB of dedicated L2 cache to increase graphics processing power. Rearranging the cache on the APU also helped to lower the power consumption, as cache tends to be fairly power hungry, and this new configuration has less overall cache on die.

AMD Excavator

Ryzen: AMD Reborn

AMD lost ground to Intel in essentially every area of the CPU market during the Bulldozer years. The company lost significant financial resources and had to sell its silicon fabs. With an uphill battle to remain in the processor market, AMD put its hopes on Ryzen.

The top end Ryzen processor, Ryzen 7 1800X, has eight CPU cores clocked at 3.6 GHz. The CPU can also accelerate up to 4.1 GHz in certain work loads. The eight cores are organized into two partitions. Each partition has 8MB of L3 cache, and each core has a dedicated 512KB L2 cache, a 64KB L1 instruction cache, and a 64KB L1 data cache. This gives the Ryzen 7 1800X a total of 16MB of L3, 4MB of L2, and 1MB of L1 cache.

In Ryzen, AMD implemented its first micro-op cache, which can store recently used instructions, improving performance and reducing pipeline stalls. Ryzen processors also support Hyper-Threading, which allows cores to handle two threads simultaneously. The company's processor debuts alongside the new AM4 socket, adding support for DDR4 RAM.

Ryzen 7 was closely followed up by its Ryzen 5 processors, which are created from semi-defective Ryzen 7 cores. Ryzen 5 is available in quad- and hexa-core variants and at similar clock speeds to Ryzen 7.

AMD Ryzen

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