Introduction:

AMD ended 2002 looking very different to the company that started it. Paper launches of processors it couldn't supply in worthwhile quantities dented confidence in the giant killing chipmaker and they saw their market share eaten away by the still mighty Intel.

Whether you run Intel or AMD processors the fact remains we need AMD on the scene. AMD are the sole reason why Intel are now pushing past 3GHz and they're the sole reason why a flagship Intel desktop processor costs less than your car. For the AMD enthusiast it needs to be recognised that AMD have consistently set new standards in aggressive processor pricing, that they've brought SMP to the masses at substantially reduced prices, and that they've done all this without once deviating for the socketA format.

All hopes seemed to be pinned on the Athlon64 and its server partner the Opteron but with this now seemingly delayed until Q3 2003 what will it take for AMD to claw back a little undoubtedly deserved respect to keep them afloat until then? They're gambling that the answer to that question might be Barton!

What is Barton?

Essentially Barton is your garden variety AthlonXP Thoroughbred B but with level2 cache doubled from 256k to 512k. As you'd no doubt expect the 333MHz FSB makes the transition to the new core though those of you expecting a 400MHz FSB are out of luck without overclocking. Shame because the overclocking results suggest it's clearly a feasible move.

Core size has increased from 84mm2 to 101mm2 to accomodate the extra L2 cache and this increased contact area may be partly responsible for what look like some very much improved running temperatures because it shares the same maximum thermal power rating of 74.3 W as the Thoroughbred cored 2800+. The typical thermal power figure quoted is actually lower for Barton at 58.4 W compared to 64 W for the 2800+.

Thoroughbred Core (left) Barton Core (right)

The picture below gives a good idea of the relative core sizes. As you can see Barton's core is basically the same width but slightly longer than Tbred.

Palomino (left) - Thoroughbred (centre) - Barton (right)

Here's how the three new processor slot in to the Athlon Stable.

And for those of you may have forgotten or who simply get some kind of strange masochistic pleasure from it, here's a potted look at the Athlon's main features.

QuantiSpeed™ Architecture for enhanced performance

• Nine-issue superpipelined, superscalar x86 processor microarchitecture designed for high performance
  
• Multiple parallel x86 instruction decoders
  
• Three out-of-order, superscalar, fully pipelined floating point execution units, which execute x87 (floating point), MMX™ and 3DNow!™ instructions
  
• Three out-of-order, superscalar, pipelined integer units
  
• Three out-of-order, superscalar, pipelined address calculation units
  72-entry instruction control unit
  
• Advanced hardware data prefetch
  
• Exclusive and speculative Translation Look-aside Buffers
  
• Advanced dynamic branch prediction

3DNow!™ Professional technology for leading-edge 3D operation

21 original 3DNow!™ instructions—the first technology enabling superscalar SIMD
19 additional instructions to enable improved integer math calculations for speech or video encoding and improved data movement for Internet plug-ins and other streaming applications
5 DSP instructions to improve soft modem, soft ADSL, Dolby Digital surround sound, and MP3 applications
52 SSE instructions with SIMD integer and floating point additions offer excellent compatibility with Intel’s SSE technology
Compatible with Windows® XP, Windows 2000, Windows ME, and Windows 98 operating systems

333MHz AMD Athlon™ XP processor system bus enables excellent system bandwidth for data movement-intensive applications

• Source synchronous clocking (clock forwarding) technology
  
• Peak data rate of 2.7GB/s
  
• Support for 64-bit bi-directional data

Athlon XP model number: 3000+ Specifications

• Cache Size: L1 - 128KB and L2 - 512KB = 640KB Total Cache
  
• Frequency / Bus / Multiplier: 2.167GHz / 333FSB / 13.0x multiplier
  
• Infrastructure Support: Socket A motherboards
  
• Fab location: AMD's Fab 30 wafer fabrication facility in Dresden, Germany
  
• Process Technology: 0.13 micron copper process technology
  
• Die Size: 101mm2
  
• Nominal Voltage: 1.65v
  
• Max Die Temp: 85 degrees Celsius
  
• Typical Thermal Power: 58.4 W
  
• Max Thermal Power: 74.3 W
  
• Icc Typical (low power state): 7.2 A
  
• Icc Typical (working state): 35.4 A
  
• Icc (processor current) Max: 45.0 A
  
  

Electrical / Thermal Specs Unique to the Athlon XP 2800+ and 2500+ (Barton core):

• Typical Thermal Power: 53.7 W
  
• Max Thermal Power: 68.3 W
  
• Icc Typical (low power state): 7.2 A
  
• Icc Typical (working state): 32.5 A
  
• Icc (processor current) Max: 41.4 A
  

In all honesty any remotely worthwhile cooler either copper or aluminium with a copper slug in the base should be absolutely fine but if you want to be pedantic and make sure all weight and clamping pressure rules are met than the current, fairly limited list of approved coolers looks like this:

The processor I get to test today is a "week 03 2003" AXDA part as can be seen below.

Why Cache Matters