Imitation To Innovation: AMD’s Best CPUs – Part 2

Duron and Sempron: AMD’s Celerons

CPU makers seem to like names that end in “on.” To compete with the Celeron and back up its Athlon, AMD released the Duron, later replaced by the Sempron. These two budget processors were generally slower than the Athlon and had less cache memory. AMD’s exclusive cache design enabled CPUs with an L2 cache that was smaller than the L1, since the latter was not mirrored in the L2 (unlike the inclusive architecture used by Intel). The Sempron is simply a re-named Athlon XP, with certain versions equipped with less cache memory (256 of 512 KB are disabled in the Thorton).

AMD Duron and Sempron

Code name	Spitfire	Thorton
Date released	2000	2004
Architecture	32-bits	32-bits
Data bus	32-bits	32-bits
Address bus	32-bits	32-bits
Maximum memory	4,096 MB	4,096 MB
L1 cache	64 KB + 64 KB	64 KB + 64 KB
L2 cache	64 KB (CPU frequency)	256 KB (CPU frequency)
Clock frequency	600-950 MHz	1,500-2,000 MHz
FSB	100 MHz (DDR)	166 MHz (DDR)
FPU	built-in	built-in
SIMD	MMX, Enhanced 3DNow!	MMX, Enhanced 3DNow!, SSE
Fabrication process	180 nm	130 nm
Number of transistors	25 million	54.3 million
Power consumption	27-41 W	62 W
Voltage	1.5–1.6 V	1.6 V
Die surface area	100 mm²	100.99 mm²
Connector	Socket A	Socket A

In addition to the Spitfire, AMD also released the Duron Morgan (based on the Athlon XP, with SSE support) and the Applebred (130 nm). The Sempron continued its career with the K8 Sempron 3400+, which is a 64-bit Sempron.

The K8: AMD Moves To 64 Bits

K8 was the first x86 processor compatible with 64-bit addressing. The architecture had other advantages such as an integrated memory controller. AMD has released a veritable army of K8-based processors since then, but we’ll concentrate on the models intended for the mainstream: the Athlon 64s. In practice, the Opteron (the server version), Athlon 64 FX (high-end) and Turion 64 (for mobile PCs) are very closely related. In general, they differ only in the management of the memory controller and cache memory, plus the type of memory used.

AMD Athlon 64

Code name	ClawHammer	Orleans
Date released	2003	2006
Architecture	64-bits	64-bits
Data bus	64-bits	64-bits
Address bus	64-bits	64-bits
Maximum memory	1 TB	1 TB
L1 cache	64 KB + 64 KB	64 KB + 64 KB
L2 cache	1,024 KB (CPU frequency)	512 KB (CPU frequency)
Clock frequency	1,800-2,400 MHz	1,800-2,600 MHz
memory controller	DDR-400, 1 channel	DDR2-667, 2 channel
FSB	800 MHz (HTT)	1,000 MHz (HTT)
FPU	built-in	built-in
SIMD	MMX, Enhanced 3DNow!, SSE, SSE2	MMX, Enhanced 3DNow!, SSE, SSE2, SSE3
Fabrication process	130 nm	90 nm
Number of transistors	105.9 million	81.1 million
Power consumption	89 W (TDP)	62 W (TDP)
Voltage	1.5 V	1.25-1.4 V
Die surface area	193 mm²	103 mm²
Connector	Socket 754	Socket AM2

Athlon 64 processors still use a PR number to indicate their ranking in the product range and there are many different versions, which generally differ in terms of cache memory and/or fabrication process. We highlighted only two models, but there are a dozen or so different K8 versions for the standard Athlon 64 alone.

Athlon 64 X2: AMD’s Dual-Core

In 2005, AMD changed its architecture to offer a dual-core version of the K8, and the Athlon 64 X2 was born. Though made up of two K8 cores, the architecture—using a HyperTransport interface—enabled good performance, unlike the solution used by Intel, with the FSB handling communication between the CPUs in its first dual-core processors. The Athlon 64 X2 exists in different sockets and is still on the market (as of August 2008) as an entry-level solution.

AMD Athlon 64 X2

Code name	Toledo	Brisbane
Date released	2005	2006
Architecture	64-bits	64-bits
Data bus	64-bits	64-bits
Address bus	64-bits	64-bits
Maximum memory	1 TB	1 TB
L1 cache	64 KB + 64 KB x 2	64 KB + 64 KB x 2
L2 cache	1,024 KB x 2 (CPU frequency)	512 KB x 2 (CPU frequency)
Clock frequency	2,200-2,400 MHz	1,900-3,100 MHz
Memory controller	DDR-400, 2 channels	DDR2-800, 2 channels
FSB	1,000 MHz (HTT)	1,000 MHz (HTT)
FPU	built-in	built-in
SIMD	MMX, Enhanced 3DNow!, SSE, SSE2, SSE3	MMX, Enhanced 3DNow!, SSE, SSE2, SSE3
Fabrication process	90 nm	65 nm
Number of transistors	233.2 million	153 million
Power consumption	89/110 W (TDP)	65/89 W (TDP)
Voltage	1.35–1.4 V	1.25–1.35 V
Die surface area	199 mm²	126 mm²
Connector	Socket 939	Socket AM2

As for the Athlon 64, we’re only showing two versions of the K8, though other versions exist. Obviously there are server versions (Opteron), high-end versions (Athlon 64 FX) and mobile versions (Turion 64 X2), and also entry-level versions in the form of the Sempron X2. One final anecdote: AMD got away with using the same code name for a processor as Intel had used: the Santa Rosa (a dual-core Opteron manufactured on a 90 nm process).

The Future Lies With Phenom

Now, in mid-2008, it’s no secret that AMD’s CPUs are struggling to keep up on the performance front. But there are a few promising prospects. Early tests of the 45 nm Phenom show interesting results and the Fusion, a cross between a GPU and a CPU, seems to be making progress as well.

Let’s hope that AMD’s financial problems are only temporary, and that they’ll be around for many more years to compete with Intel in the x86 processor arena.