SPECIAL REPORT
MONDAY, MARCH 20, 2000
Who's Faster at 1 GHz? AMD or Intel?
Michael J. Miller, Editor-In-Chief
PC Magazine
Now that we've tested 1 GHz systems built around CPUs from both AMD and Intel, here are some things we think you need to know.
YES, THEY'RE EXPENSIVE
Depending on the type and amount of system and graphics memory, 1 GHz PCs range from $2,600 to $4,300. Who will pay? One obvious market is gamers, who can never get enough 3D graphics performance. But there are plenty of other practical applications as well, such as video editing, 2D and 3D modeling and speech recognition.
YES, THEY'RE FASTER
1 GHz processors raise the bar on desktop performance in all three of the key areas we test -- business applications, Internet tasks and 3D and gaming. But not all 1 GHz PCs are created equal. The actual performance of individual systems depends on much more than clock speed. Other factors such as the architecture of the processor, the other system components and how they are connected all play major roles.
AMD AND INTEL EACH HAVE ADVANTAGES
The AMD Athlon processor has some core technological advantages that let it execute more RISC-like internal instructions per cycle and often decode more x86 instructions at a time. Its floating point unit is more advanced than PIII, and this is reflected in its high scores on our floating-point tests (FPU WinMark 99).
On the other hand, the Pentium III's onboard cache is more efficient, which helped in many of our tests. To raise the clock speed of their processors, AMD and Intel have to increase the voltage (to 1.8 volts for the Athlon/1 GHz and 1.7 volts for the Pentium III/1 GHz). As the Athlon's voltage increases, its core speed is increased, but the speed of its L2 cache does not keep up. In the Athlon/1 GHz, the L2 cache runs at one-third the processor's speed, or 333 MHz. By contrast, the Pentium III's onboard L2 cache runs at the full processor speed.
Also note that the Pentium III's Streaming SIMD Extensions (SSE) and the Athlon's Enhanced 3DNow! instructions are very similar. Both are designed to improve performance on graphics, audio, video and speech recognition. SSE can load twice the amount of floating-point data per instruction from memory at once (four 32-bit single-precision floating-point entries versus two for the Athlon). Athlon can execute four 32-bit FP operations at a time (Athlon has two 64-bit 3DNow! Units). PIII is similar with similar throughput.
The SSE instruction and data-load efficiency (resulting in fewer instructions needed per 3D vertex than 3DNow!), combined with DirectX 7's use of SSE's granular prefetch instructions and streaming stores (to better manage data placement in the cache hierarchy and reduce cache pollution), and PIII's high-speed L2 cache may all help to explain why Pentium III-based systems perform so well on our 3D Winbench Processor Test.
INTEL TOPS IN PERFORMANCE, NOT PRICE
Clock speed for clock speed, systems using Intel's high-end processors currently outperform those using AMD's Athlon chip. However, Pentium III-based systems are also more expensive, so in choosing a high-end PC you'll need to weigh the performance margin against the extra cost.
Of course these price premiums won't last long. As faster processors arrive, prices will drop and eventually 1 GHz will seem like yesterday's news. In fact, AMD has already demonstrated a 1.1 GHz Athlon and said future Athlons will also have full-speed onboard L2 cache. Intel recently demonstrated a whole new architecture at 1.5 GHz (code-named Willamette) that is nearing completion.
To learn more about the specs of the systems we tested and to see all the benchmark test results, be sure to read our full evaluation. Click for more zdnet.com |
