AMD Athlon "Thunderbird" 1 GHz / 800 MHz

Conclusion

If you were expecting the Thunderbird to completely wipe away the competition then you're most likely going to be dissappointed by its performance. However if you understand that the whole point for moving the Athlon's L2 cache on-die was to make way for higher clock speeds without diminishing performance returns, then the Thunderbird makes a much more lasting impression.

Considering that the Thunderbird is going to be priced the same (from AMD at least) as the older Athlons there is no reason for you to want to purchase an older Athlon unless vendors begin discounting them heavily. However if you're currently an Athlon owner, the investment you made in your processor is probably too great to just throw away so you can get a Thunderbird. The performance improvement over the Athlon is not great enough to make you want to upgrade if you already have an Athlon running (either regularly clocked or overclocked) at 700MHz or above.

The fastest official platform for the Pentium III is still the i820 + RDRAM setup which is still entirely too expensive to justify the relative lack of a performance increase over competing platforms. Clock for clock the Thunderbird is generally faster than the Pentium III on all of its official platforms (BX, 820, 133A) although in some cases the Thunderbird is edged out by the Pentium III on an 820 + RDRAM setup.

If you compare the Thunderbird on a KT133 motherboard to a Pentium III on a VIA 133A motherboard you can see that the Athlon holds a large advantage over the Pentium III, but you can also see that the Athlon is being severely limited by the performance of the KT133 chipset. Compared to the BX and 820 chipsets the VIA 133A definitely lags behind, and since the KT133 is based on the same AGP core and features the same memory controller as the VIA 133A you can expect to see the same subpar performance with that part as well. If you compare the Athlon on a KT133 platform to an overclocked BX133 setup you will truly be able to see how much of a limitation the KT133 chipset is for the Thunderbird.

Unfortunately there is not much hope in the near future for the Thunderbird chipset situation. The next big chipset release that you'll want to watch out for will most likely be AMD's 760 chipset which will be released around the time of the Mustang core. The chipset itself, will support DDR SDRAM and the 133MHz DDR FSB (effectively 266MHz) and should provide everyone with the performance improvement we've been hoping for. If you currently have an Athlon, the release of the AMD 760 chipset is probably when you'll want to upgrade your setup if you were thinking about doing so.

In a couple of weeks we will be releasing performance figures on AMD's Duron, their low-cost version of the Athlon. For those of you that are about to dive into the Athlon platform you may want to wait until Duron is released before making your final decision. If you're already content with the benchmarks you see for the older Athlons (512KB L2) then the Duron may be all that you need since it will generally perform between 90 - 100% of the speed of an equivalently clocked Athlon (not Thunderbird). The major benefit the Duron has going for it is its extremely low cost, there is no question that the Duron will end up dominating the low end market where Intel's Celeron has failed to perform as well as we expected.

To summarize this all, if you want the fastest Athlon then go for the Thunderbird, if you were about to purchase an Athlon wait for the Duron, it's just about as fast, and if you're currently an Athlon owner wait for the AMD 760 chipset before upgrading, it's not worth it right now. If you're borderline between purchasing an Athlon or a Pentium III, the latter will only hold a major performance advantage if you're going to be running on an overclocked BX platform. Otherwise the decision is pretty much a toss up and one that only you can make for yourself. The only suggestion we can make is to stay away from the 820 + RDRAM platform for now, it is entirely too expensive for an end user; unless the price of RDRAM comes down there is no reason to pursue the platform. The best chipset for the Pentium III still seems to be the BX, albeit in overclocked form, so if you're going to be going down the Pentium III route you're probably better off using a BX based board.