Benchmark Analysis

In terms of overall performance, the Athlon XP 1900+ is one impressive piece of silicon. It not only rules the roost in most system and game benchmark tests, but it comes very close to ousting the Pentium 4-2.0 GHz from it's Quake 3 perch, and beats it soundly in Serious Sam testing. After being surprised by the speed of the Pentium 4 reaching the 2.0 GHz level, AMD has played the same trick on Intel with a quick 1-2 of Athlon XP 1800+ and 1900+ releases with absolutely no response from the Intel camp.

This doesn't mean that the Athlon XP is a clean winner, as the Pentium 4-2.0 GHz showed some extreme staying power in the 3DMark 2001 testing (which may pay dividends with upcoming games) and still holds the Quake 3 key for now. What the Athlon XP has done is make their application lead even wider and eat into Intel's Quake 3 scores. After this impressive showing, the Athlon XP 1900+ should be accorded its due respect as the fastest overall desktop processor.

Overclocking

The Athlon XP has to be one of the prime overclocking targets to come out in a long time. Both the Athlon and Duron processors were excellent overclockers, mostly due to their unlocked nature or the ease in which even the locked versions were able to be undone. Whether you made sure to buy an unlocked version off the shelf or used a variation of the infamous "pencil trick", both Athlon and Duron CPUs were, and still are, a favorite of the tweaking crowd.

But something funny happened on the way to Athlon XP overclocking nirvana; AMD put their foot down hard! The first step was to actually score the bridges controlling the clock rate, thereby leaving a large pit between bridge connections. This was pretty surprising given AMD's previous stance against permanently locking processors, but many enterprising individuals either got hard at work filling in the bridge pits, or used one of the retail solutions available, such as the popular "bridge tape". Things went well until the latest AMD jab, which was to cover the physical bridge connectors with some sort of ceramic or epoxy covering, thereby rendering bridge tape useless. Some online vendors have even halted sale of this tape, and are offering refunds because of these newer Athlon XP versions.

Any processor company has the right to protect their product from being operating out of spec, but the lengths AMD has gone are very surprising. And at a certain point, it may be better to just accept these new Athlon XP processors as clock-locked rather than attempting to scrape or wash away the bridge covering. For all but the most risk-tolerant of performance freaks, fooling around with the clock settings on the current Athlon XP is just not a viable option. The clock protections are a bit too rigid and the potential of toasting your processor a bit too high for our tastes.

That still leaves us the old stand-by of using front-side bus increases, but this route has a great deal to do with your system components than anything else. In addition to requiring a prime PSU and high quality memory, the inherently higher AGP and PCI speeds can take a toll on your system components. Newer AGP cards can usually handle a higher AGP speed, but certain hard drives, PCI cards (especially of the SCSI variety) and other important (and sometimes costly) components can be put under a huge strain by going this route.

Upgrades and Platforms

The Athlon XP has generated a great deal of interest in the upgrade market, and the prospect of gaining noticeable speed increases by just slapping in a new CPU is an attractive option, but it is by no means a sure bet. Sure the Athlon XP is still based on the Socket A design, but there are important differences in the bus timings that can turn a simple upgrade into a serious gamble.

In our reference testing using older VIA KT133A and AMD 761 platforms, we found a huge divergence in Athlon XP support. Some boards purportedly supported the new CPU with only a BIOS upgrade, while others required a newer revision for full support. From our experience, upgrading a non-supported revision (even with a BIOS upgrade) is a chancy affair, as it may actually work but usually holds some stability issues. Even with a supported revision and new BIOS, you are in no way guaranteed a seamless upgrade.

And then there is the famous line between the Athlon XP 1800+ and 1900+ processors, with many boards supporting up to the 1800+, but no further. Initially, we thought that the boards in question were just waiting for AMD certification, but it seems to go a bit deeper than that. We are as yet unsure of any changes relating to the new Athlon XP 1900+, but various motherboard support inquiries have made the 1800+/1900+ division quite clear.

We tested a few KT133A and AMD 761 motherboards (revision and BIOS certified from the motherboard manufacturer) with both the Athlon XP 1800+ and 1900+ and even though some motherboards worked and some didn't, only in a select few of those upgrade scenarios did the system feel 100% stable. From our test sample at least, the Athlon XP 1900+ should be a well-researched upgrade that you think long and hard about. Also give a lot more credence to the AMD Approved Motherboard List for the various Athlon XP speeds, rather than rely on the information that a particular vendor states on their website.

For our money, buying into one of the new Athlon XP platforms like the KT266A is a far safer choice and a higher performance one to boot. Once we loaded the 1900+ on the EPoX EP-8KHA+, the change in the Athlon XP's behavior was incredible. No longer did it feel like we were running on (or just over) the bleeding edge of our system's capabilities, and the entire KT266A installation and software load went very smoothly. We also did not experience a single crash or problem during the entire test period.

There is no doubt that the AMD Athlon XP is a processor that is best served by a brand new platform architecture, and the differences between using it with an older revision AMD 761 board and a new KT266A can be quite startling. Plus, with many KT266A boards having sub-$100 price tags, moving up to a new Athlon XP/motherboard combo doesn't have to be an expensive proposition.

CPU Core Heat

Outside of pure speed, one of the most important benefits of the Athlon XP is the prospect of lower core heat levels. Who hasn't looked at the 50+ degrees Celsius core temperatures of their high-end Athlon and wished that this level of performance could be available with a bit less heat? Well, the Athlon XP may be the answer, and even with the 1.6 GHz Athlon XP 1900+, we experienced core temperatures in the range of 43-46 degrees Celsius (depending on load). This testing was performed with a higher-end Copper HSF, but even with a basic Taisol Athlon unit, temperatures never went above 48 degrees Celsius.

These results are taken from a very basic mid-tower configuration, without serious case cooling supplied, and adding a few fans into the equation yielded some noticeable temperature drops. In many ways, the lower core heat of the Athlon XP is actually one of its most important features. Even at 1.4 GHz, the Athlon is one hot little customer, but the 1.6 GHz Athlon XP 1900+ runs at a higher clock rate and still yields a lower core temperature.

An interesting side note to this related to our upgrade experiments. Since system stability was far from optimum under certain upgrade platforms, the natural inclination was to increase the CPU cooling. This led us to purchase some higher-end HSF units, but even these did not alleviate the problem. It wasn't until we setup our KT266A system that it became clear that the motherboards were the problem and not the CPU. Using the EPoX board, we were able to use any of our Athlon HSF models with absolutely no degradation in system stability.