According to AMD, Bulldozer-based CPUs are based on GlobalFoundries's 32 nm Silicon on insulator (SOI) process technology and reuses the approach of DEC for multitask computer performance with the arguments of, according to press notes, "balances dedicated and shared computer resources to provide a highly compact, high units count design that is easily replicated on a chip for performance scaling." In other words, by eliminating some of the "redundant" elements that naturally creep into multicore designs, AMD has hoped to take better advantage of its hardware capabilities, while using less power.
Bulldozer-based implementations built on 32nm SOI with HKMG arrived in October 2011 for both servers and desktops. The server segment included the dual chip (16-threads) Opteron processor codenamed Interlagos (for Socket G34) and single chip (4, 6 or 8 threads) Valencia (for Socket C32), while the Zambezi (4, 6 and 8 threads) targeted desktops on Socket AM3+.
Bulldozer is the first major redesign of AMD’s processor architecture since 2003, when the firm launched its K8 processors, and also features two 128-bit FMA-capable FPUs which can be combined into one 256-bit FPU. This design is accompanied by two integer clusters, each with 4 pipelines (the fetch/decode stage is shared). Bulldozer will also introduce shared L2 cache in the new architecture. AMD's marketing service calls this design a "Module". A 16-threads processor design would feature eight of these "modules", but the operating system will recognize each "module" as two logical cores.
The modular architecture , consist of multithreaded shared lv2 cache and FlexFPU which uses simultaneous multithreading however 2 physical integer cores in module are single threaded in contrast with Intel's Hyperthreading where 2 virtual simultaneous threads share resources of single core.
The first Bulldozer CPUs were met with a mixed response. It was discovered that the FX-8150 performed poorly in benchmarks that were not highly threaded, falling behind the second-generation Intel Core i* series processors and being matched or even outperformed by AMD's own Phenom II X6 at lower clock speeds. In highly threaded benchmarks, the FX-8150 performed on par with the Phenom II X6, and the Intel Core i7 2600K, depending on the benchmark. Given the overall more consistent performance of the Intel Core i5 2500K at a lower price, these results left many reviewers underwhelmed. The processor was found to be extremely power-hungry under load, especially when overclocked, compared to Intel's Sandy Bridge.
The Tom's Hardware website commented that the lower-than-expected performance in multi-threaded workloads may be because of the way Windows 7 currently schedules threads to the cores. They point out that "if Windows were able to utilize an FX-8150's four modules first, and then backfill each module's second core, it'd maximize performance with up to four threads running concurrently." This is similar to what happens on Intel CPUs with HyperThreading – Windows 7 "schedules to physical cores before utilizing logical (HyperThreaded) cores."
On 13 October 2011, AMD stated on its blog that "there are some in our community who feel the product performance did not meet their expectations", but showed benchmarks on actual applications where it outperformed the Sandy Bridge i7 2600k and AMD X6 1100T.
On 6 March 2012, AMD posted a knowledge base article stating that there was a compatibility problem with FX processors, and certain games on the widely used digital game distribution platform, Steam. AMD stated that they had provided a BIOS update to several motherboard manufacturers (namely: Asus, Gigabyte Technology, MSI, and ASRock) that would fix the problem.
On 31 August 2011, AMD and a group of well-known overclockers including Brian McLachlan, Sami Mäkinen, Aaron Schradin, and Simon Solotko managed to set a new world record for CPU frequency using the unreleased and overclocked FX-8150 Bulldozer processor. Before that day, the record sat at 8.309 GHz, but the Bulldozer combined with liquid helium cooling reached a new high of 8.429 GHz . The record has since been beaten at 8.58 GHz by Andre Yang using LN2
2nd generation CPU piledriver is the AMD given codename to an improved microarchitecture based on Bulldozer. AMD Piledriver cores are found in Socket FM2 Trinity and Richland based series of APUs and CPUs and the Socket AM3+ Vishera based FX-series of CPUs.
Piledriver is a microarchitecture developed by AMD as the successor to Bulldozer. It primarily targets the desktop, mobile, and server markets.
The changes over Bulldozer are largely incremental. Piledriver uses the same 'module' design with main improvements to branch prediction and FPU/integer scheduling, along with a switch to hard edge flip-flops to improve power consumption. In practice this resulted in clock speed gains of 8–10% and a performance increase of around 15% with similar power characteristics. FX-9590 is around 30%-35% faster than FX-8150 on stock speed thanks to far higher clock rate. Products based upon Piledriver were first released on 15 May 2012 with the launch of the Trinity series of mobile Accelerated Processing Units. APUs aimed at desktops followed in early October 2012 with Piledriver-based FX-series CPUs released later in the month. Opteron server processors based upon Piledriver launched in early December the same year.
3th generation CPU steamroller is a microarchitecture under development by AMD to succeed Piledriver in the second half of 2013.
In 2011, AMD mentioned (by name) a third-generation Bulldozer-based line for 2013, with working title Next Generation Bulldozer, on the 28 nm manufacturing process.On 21 September 2011, leaked AMD slides indicated this third generation of Bulldozer core was codenamed Steamroller. Steamroller will still feature two core based modules found in Bulldozer and Piledriver designs.The focus of Steamroller is for greater parallelism.Improvements will center on independent instruction decoders for each core within a module, better instruction schedulers, larger and smarter caches, more internal register resources and improved memory controller. AMD estimates that these improvements will increase instructions per cycle up to 30%.
4th generation CPU excavator is a microarchitecture under development by AMD to succeed Steamroller. On 12 October 2011, AMD revealed Excavator to be the codename for the 4th generation Bulldozer core, scheduled for 2014 release.It is thought that Excavator will initially be implemented in the 4th Generation A-series Fusion APU line in 2014, while a revised version will be adopted in 2015 for the FX-series and Opteron lines.