When IDT announced the C6 CPU in the first half of this year it came as quite a surprise to most of us. The C6 became then the star of the Computex show in Taipei in June this year. After this first introduction it became pretty quiet around IDT again and only now this new Socket 7 CPU starts shipping. Targeted against the Intel Pentium MMX, IDT claimed that the C6 has got about the same integer performance at the same clock speed as the Pentium MMX. IDT was also not making any secret of the fact that the floating point as well as the MMX unit of the C6 will not be as fast as in the Intel Pentium MMX. The C6 is targeted to the lower end market, similar to the lower clocked versions of the AMD K6 and the IBM/Cyrix 6x86MX CPUs. The special trick of IDT is supposed to be the fact that the chip is fairly small as well as requiring only little power and IDT is therefore pretty confident of raising the clock speed to up to 400 MHz soon as well as using the C6 in notebooks where low power consumption is crucial.
The architecture of the C6 is much less sophisticated than the architecture of its competitors AMD K6 and IBM/Cyrix 6x86MX. No 'register renaming' or 'out of order execution' is used here for reaching Pentium MMX performance but simply a large L1 cache in cooperation with a pretty classic but straight forward microprocessor design.
At the Computex in June IDT only showed a few systems with C6 CPUs running at 150 or 180 MHz. I also had one 150 MHz engineering sample a few months ago which couldn't really impress me a lot. Now IDT shipped a whole system to me with a 200 MHz C6 so that I could test if this new Socket 7 CPU is living up to its claims. I compared the C6 200 to the Intel Pentium MMX 200, the AMD K6 166 and 200 and the IBM/Cyrix 6x86MX PR2 166 (running at 133 MHz) and PR2 200 (166 MHz). The price of the C6 200 lies pretty much somewhere in between these CPUs, with the Intel Pentium MMX as the most expensive, the IBM/Cyrix 6x86 PR2 166 as the cheapest.