IDT Winchip 2-3D

by Anand Lal Shimpi on January 16, 1999 12:31 AM EST

The Winchip 2-3D

Taking advantage of the oversight of virtually all microprocessor manufacturers, IDT decided it was about time to stop fighting for control of the world and start tailoring to the needs of the users that don't have the interest or the funds (or both) to pursue a new upgrade every 6 months. This is where the new Winchip 2-3D comes into play.

winchip.jpg (11749 bytes)

The Winchip 2-3D is a Socket-7 processor, and by saying that you immediately know that it doesn't require a Super7 motherboard to run at its maximum potential, this is a good, old fashioned, Socket-7 processor. The processor is specified for operation in one of two voltage ranges, 3.52v (3.45v - 3.6v), or 3.3v (3.135v - 3.6v), this is just to make sure that regardless of what type of Socket-7 motherboard you have, the Winchip 2 will work in it. In spite of the greater than normal voltage requirements of the chip, the Winchip 2 runs extremely cool. The 0.25 micron chip runs quite cool, consuming less than 16 Watts of power at 266MHz (most processors consume in excess of twice that number, therefore running at a much higher temperature) and occupying a total die area of 58 mm2. Making sure that all competing chips which run at much lower voltages run at much higher temperatures than the Winchip 2, the sole purpose of the unusually high voltage requirements is for backwards compatibility.

The unique nature of the Winchip 2 makes it ideal for low power environments, especially notebooks, however it is doubtful that you'll see too many Winchip 2 based laptops simply because of the demand for the chip.

The only requirements for running a Winchip 2 processor in your Socket-7 motherboard are support for the 66MHz front side bus frequency (standard on all Socket-7 boards), and a 1.5x, 2.0x or 3.0x clock multiplier (standard on all Socket-7 boards), and a BIOS update for Winchip 2 support (available from your motherboard manufacturer). Chances are that you'll meet all of those requirements, even if you have an older 430FX Socket-7 motherboard, and if that is the case, then you'll be tempted by the rest of the Winchip 2 specifications.

The Winchip 2 brings quite a powerful set of features to the table with its introduction, a full 64KB L1 cache split into the conventional 32KB 4 way set associative data and 32KB 2 way set associative instruction set cache brings the Winchip 2 to the level of AMD's K6 and K6-2 line of processors in terms of a highly advanced core. The amount of L1 cache on the chip of the Winchip 2 is already twice that of the Pentium II, and is obviously where a great percentage of the business performance of the processor is derived from, don't interpret this incorrectly though since the Winchip 2 is definitely not a competitor to the Pentium II in terms of performance.

Also following in the footsteps of AMD, IDT chose to license the 3DNow! instructions to be used along side the two independent MMX units on the Winchip 2. Unlike Intel's utterly disappointing MMX technology, the inclusion of the 3DNow! instructions on the Winchip 2 breathes new life into the possibility of the Winchip 2 being a processor that'll even tailor to the needs of the gamer, to a certain extent of course. For those of you not familiar with AMD's 3DNow! instructions, a brief explanation of their application is as follows: (taken from the AnandTech AMD K6-2 Review)

3DNow! exploits a technology known as Single Instruction Multiple Data execution, or SIMD for short. What this technology does is, as the name implies, it applies a single command (or instruction) to multiple sets of data simultaneously. A real life example of something like SIMD execution would be much like picking berries. Instead of picking a berry off of a bush, washing it, then returning to the bush to collect more you could simply collect a handful of berries at once and retrieve them simultaneously. The key to understanding SIMD is the simultaneous execution of the instruction, therefore saving time. SIMD is not the only benefit the Winchip 2 receives from AMD's 3DNow! instructions, however it is definitely a plus. If you have ever written any code that requires heavy floating point calculations you will know that floating point division is an extremely slow process from the perspective of the CPU. AMD saw this as a major problem and integrated a reciprocal multiplication function into their 3DNow! instruction set. For example, instead of dividing a number by 4, using reciprocal multiplication you can achieve the same result by simply multiplying by the fraction 1/4. While this may not seem like much, you must understand that a processor can multiply faster than it can divide, in this case, instead of dividing by 4 you are multiplying by 1/4, which can make a world of difference in terms of performance on a more complex level. Since the reciprocal multiplication function is hard-coded on the Winchip 2's 3DNow! units it actually provides a healthy performance increase in many situations.

IDT's support for 3Dnow! is a win for both AMD, since their technology will begin to grow its roots in a market unique to IDT customers, and at the same time it is a win for IDT, as their FPU and gaming performance has been improved with the Winchip 2 to a point where playing the occasional game of Quake 2 on a Winchip 2 based system isn't horrendously slow (keep in mind that it isn't blazing fast either).

The Winchip 2 will be initially offered in a number of flavors:

The many flavors of the Winchip 2
Courtesy of IDT Winchip 2 Documentation

The effects of an increased FSB frequency on the Winchip 2, as is the case on the Cyrix M2, isn't all that great (relatively speaking in comparison to the AMD K6 or Intel Pentium MMX). This is one reason why the Winchip 2 is available in normally unacceptable speed settings for Socket-7 processors (i.e. 240MHz). The first revisions of the Winchip 2 will only allow for integral clock multipliers (i.e. 2.0x, 3.0x, 4.0x), with the commonly used 1.5x/3.5x clock multiplier being remapped to the 4.0x internal setting on the Winchip 2 to extend backwards compatibility for users that want to make use of the 266MHz chips. Later versions of the chip will support the 100MHz FSB, and will be intended for true, low-cost upgrades for Super7 users, however for now the K6-2 still seems to be the most affordable and highest performing Super7 solution, in spite of the < $60 price tag of the Winchip 2. The upcoming 233, 250 and 266MHz Winchip 2 offerings will be made possible using 2.33, 2.5, and 2.66 clock multipliers that will be mapped to internally to allow for complete backwards compatibility for older motherboards (meaning a 2.0x setting on your motherboard could result in a 2.33x clock multiplier for the CPU itself). Not a bad immediate roadmap for a "low-cost" processor.

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