Aaron - Re:" a direct competitor of Intel's has produced a chip which is
superior both in price and performance to Intel's top-of-the-line chips...."
You have to be very careful here to avoid being "lied to by the statistics".
The Cyrix 6x86 has several advantages over the Pentium, the most compelling is an on chip L1 cache of 32 KBytes, vs. the 16 K for the Pentium & Pentium Pro.
Any benchmark test which takes advantage of an L1 cache of 32K, and "penalizes" a cache of 16K (with cache misses), will result in a test showing the 6x86 is faster than a Pentium. For this particular test, it is faster. But one test does not make a CPU.
The 6x86 also incorporates a number of architectural features not found in the Pentium, but found in the Pentium Pro - Out of order execution, speculative execution, and register renaming to mention a few. From this standpoint, the 6x86 is more like a Pentium Pro rather than a Pentium. This is most likely a result of the 6x86 design being done about two years after the Pentium - and probably in parallel with the Pentium Pro.
Again, the 6x86 will have performance adavantges over a Pentium where these architectural feaures come in to play.
NOW....the drawbacks. The 6x86 has a floating point unit (FPU) that is slower than the Pentium FPU by anywhere from 25% to 50%. This is a dramatic drawback of the Cyrix 6x86.
Truth be told, not all software makes use of an FPU. Word processors generally don't. However, spreadsheets (working with non-integer numbers), CAD packages, databases with non-integers (most currency entries), etc. all make use of the FPU. Rendering, as done on many graphics packages, notably Adobe Photoshop, are also FPU intensive. And, many "games" make use of the FPU, such as Quake, Doom, etc. (Big deal, in my opinion).
Thus, any benchmark tests that involve FPU action will show that the Pentium is much faster than a Cyrix 6x86 when these FPU instructions are intensive,
So, beware of benchmarks and used car salesmen. You never know what to believe.
Intel has enlarged the caches on the Pentium MMX and Klamath chips - from 16K to 32K, so they will nullify the cache advantages of Cyrix's 6x86. However, Cyrix's M2 (their next "6x86") will have a humongous cache of 64Kbytes - so beware. New benchmark tests will be drummed up to show that this chip is faster than the speed of light.
As for price advantages, if Cyrix chooses to sell their chips for less than the equivalent Pentium, the 6x86 will be cheaper. BBUUTT - it is very expensive to make. The 6x86 is HUGE - as per the following table:
Technology .....Size(mm2)...........Metal Layers
Intel Pentium .........035u ..........90 ..................4
Cyrix 6x86 .............0.44u ..........156 ..................5
Thus, the 6x86 is nearly twice the size, and therfore at least twice as expensive as the Pentium. Result - little or no profits for Cyrix.
Cyrix has recently shrunk the 6x86 to 0.35 micron geometries, but I don't think they are shipping this yet. Besides, they have an inventory of 400,000 to 600,000 unsold 6x86 chips of the older, larger die - all which consume much more power than their equivalent Pentium brethren.
Paul |
