Advanced Micro Devices (AMD) seems to have erased the last, small performance edge enjoyed by Intel's high-end desktop CPUs.

AMD's Thunderbird, which was launched on Monday (5 June), features an integrated level-2 memory cache, a design trick that buys more performance at no cost to the customer.

Systems powered by the Thunderbird, a catchy code name that AMD is changing to "Athlon with performance-enhancing cache memory," will initially be in short supply.

Both AMD and Intel have taken to launching chips weeks before PC makers are ready to build systems with the new chips in significant quantities.

Nevertheless, the new systems should be worth the wait. Initial tests by PC Advisor US sister publication PC World on a new 800-MHz Athlon system suggests that the new chips indeed offer more processing power for your money.

Business performance indicates that an enhanced Athlon-based system running at 800 MHz is comparable to a 1-GHz system powered by the original Athlon. And the 800-MHz Thunderbird system was just as fast as the 800-MHz Pentium III-based systems that have been tested in the past.

What makes Thunderbird fly? It's the on-chip L2 cache. The original Athlon chips offered 512KB of L2 cache - but the cache resided off the chip - meaning it ran at just one-half to one-third of the chip's clock speed, depending on the particular processor.

The new Athlon chip's 256KB of L2 cache is integrated into the processor, so the memory runs at full speed. Intel's Pentium III CPU has had on-die, full-speed L2 cache since last October. Now AMD is catching up.

AMD is launching the new processor in six speeds: 750 MHz, 800 MHz, 850 MHz, 900 MHz, 950 MHz, and 1 GHz.