ALMOST Athlon internal thermal diode

[Rapier]

By Chris Angelini
Published: 11/5/2001

Without giving Intel a chance to respond to the Athlon XP 1800+ launch last month, AMD has readied the Athlon XP 1900+ as the successor to its current flagship processor. Continuing the new "performance rating" naming scheme, AMD's latest uses the 1900+ suffix, though the processor actually runs at 1.6GHz. Like the 1800+ before it, the 1900+ incorporates all the enhancements made to the Palomino core, similar to the mobile Athlon 4 and the Athlon MP launched earlier this year.

Those unfamiliar with AMD's new naming convention--which was introduced with the Athlon XP launch--may find it to be confusing. While AMD says that the naming scheme is intended to communicate the Athlon XP's architectural superiority over previous Athlon processors, it is clear that AMD also wants to combat the clock frequency advantage held by Intel's 2.0GHz Pentium 4. System performance is still often viewed as a factor influenced primarily by clock frequency, when in reality, it's much more complicated than that. While Intel has focused on clock speed, AMD continues to emphasize that the work done per clock cycle is equally important for overall performance. For the time being, AMD appears to be rating its processors very conservatively, as the Athlon XP 1900+ is rated for comparison with Intel's Pentium 4 1.9GHz, but it is clearly faster than the 2.0GHz Pentium 4 in a majority of tests.


Athlon XP 1900+
The most obvious change made to the Athlon involves packaging, or how the silicon CPU is prepared to interface with the motherboard. Rather than use the rigid green ceramic substrate to seat the processor core, AMD has transitioned over to a brown fiberglass Organic Pin Grid Array (OPGA) that offers more efficient power delivery. Beyond the visible changes, the Athlon XP also features improved data prefetching, allowing the processor to take advantage of unused memory bandwidth for fetching data that may be needed before it is actually called upon. Additionally, 3DNow! has been expanded to include SSE instructions, which lets the Athlon XP take advantage of the SSE optimizations in many applications. Unfortunately, this new 3DNow! Professional feature requires operating system and BIOS support, which makes the upgrade process slightly more difficult than swapping in a new chip. The translation look-aside buffers have been enhanced, which means that the process of locating data within system memory has theoretically been sped up. The last improvement made to the Athlon XP is the inclusion of an internal thermal diode for monitoring heat. Taking advantage of the diode requires BIOS support on the part of the motherboard manufacturer--something yet to be fully implemented in any available board.


EPoX KT266A Motherboard

As good timing would have it, VIA, SiS, and Nvidia have all developed Athlon-compatible platforms that combine impressive stability with aggressive performance. In fact, most major motherboard manufacturers are on the verge of shipping products based on VIA's KT266A chipset, which augments the performance of the mediocre KT266 chipset that we reviewed in July. Changes to the chipset include both an improved memory controller and deeper internal buffers designed to keep the host processor continually fed with data.

Now that stable, high-performance platforms are more readily available for the Athlon, AMD is taking the opportunity to phase out its 760 chipset. Since motherboards based on AMD's popular chipset will become harder to find, we have updated our test systems with EPoX's EP-8KHA+ KT266A motherboard.

[LawyerRon]

Michael,
So what you're saying is that the XP1900+ is faster than my Cely 500?

You're making me feel bad!

I think I'm starting to want one of those XPs.

[Carl Price]

Originally posted by LawyerRon Michael, So what you're saying is that the XP1900+ is faster than my Cely 500? You're making me feel bad! I think I'm starting to want one of those XPs.

Find something to hold on to. The feeling will pass.

[Rapier]

Michael,
So what you're saying is that the XP1900+ is faster than my Cely 500?

You're making me feel bad!

I think I'm starting to want one of those XPs.



I have a real PIII 500. Were you able or do you intend to upgrade to Win XP?

[LawyerRon]

Michael,
Why?

My little Cely chugs right along on Win98SE.

Maybe one day when I build a new system but I just don't see any benefit right now. I use this system primarily for web surfing and office apps anyway. That's why I'm in no hurry to build something faster.