Intel Chips
Pentium
The original Pentium processor was released in 1993. Intel had not been able to copyright this brand of processor for legal reasons using the label 586. Thus, they created a new name for their next generation of processors: Pentium.
The Pentium processor was originally developed at speeds of 60 MHz and 66 MHz. Soon after, Intel marketed 75MHz, 90MHz, 100 MHz, 120 MHz, 133 MHz, 150 MHz, 166 MHz, and 200 MHz flavors, which were really just multipliers of the original 60 MHz or 66 MHz systems.
As with clock double and clock triple in the case of the 80486s, we now have the same marketing technique in the case of the Pentium, the only difference being that the Pentium motherboards ran at either 60 MHz or 66 MHz. For example, a 120 MHz computer has a processor running at 120 MHz while the system board runs at 60 MHz, which meant that the processor runs twice as fast as the rest of the system.
From a consumers point of view, clock multipliers become important when you take a look at computers such as the Pentium 133 or the Pentium 150. Which is faster? The obvious answer is the system with the higher megahertz speed. But is it really? The Pentium 133 is a clock double of the 66 MHz board, while the Pentium
150 is a clock double and a half of the 60 MHz board. Table 2-3 compares the speed of the motherboard and processor for the different Pentium systems.
By looking at the system board speeds of the Pentium 133 and the Pentium 150, you could assume that the computer running the Pentium 133 may be able to keep up with, if not outperform, the one running the Pentium 150.
The Pentium processor had a 32-bit address bus, 32-bit registers, and a 64-bit data bus. The Pentium took the 8K of L1 cache that was found on the 80486 and doubled it to 16Ktwo 8K channels. One channel was for data cache and the other for application code cache.
Heat sinks and CPU fans
Due to the size of the Pentium processor and the number of transistors passing current, the chip reached undesirable levels of heat, which caused it to become unstable. Thus, many of the Pentium processors came with either a cooling fan or heat sinks.
Heat sinks are a group of metal-like pins that are placed on the chip to draw heat away from it. A cooling fan is a small fan placed on top of the processor. The function of the cooling fan is to pull the hot air away from the processor, helping to keep the processor cool. Some processors may get so hot that a heat sink may not be enough of a cooling device; in this case, the manufacturer may place a fan on top of the heat sink. Figure 2-6 shows you what a heat sink looks like.
Superscalar design
Before the Pentium came along, processors used one instruction pipeline. This meant that when an application executed, it would run each stage of the application job one step after the other. For example, if an application has three lines of code, as seen in Figure 2-7, each line of code can only be processed after the previous line of code is fully completed. This creates a delay, or wait time, that slows performance.
The Pentium processor has two instruction pipelines, named U and V. Having two instruction pipelines enables the processor to execute two instructions at the same time. Thus, the three lines of program code, shown in Figure 2-8, can be quickly executed on a Pentium processor because Lines 1 and 2 are processed at the same time, causing Line 3 to be processed that much faster. Notice that Lines 1 and 2 execute parallel to one another; therefore, parallel processing is taking place.
An application would have to be designed to take advantage of two instruction pipelines. These applications could be labeled something like Pentium Aware or Pentium Ready.
MMX
After the Pentium was developed, Intel introduced MMX (multimedia extensions) technology. MMX comprised 57 new instructions that were built into the processor and told the system how to work with audio, video, and graphics. If these instructions were not built-in, the processor would have to retrieve them from somewhere else. Since both the home and business user seemed to be heading towards the world of multimedia, it made sense to enhance the processor and make it multimedia- aware. Running any kind of multimedia application on a processor that supports MMX will give you a major performance increase.
MMX also increases the L1 cache by 16K, so any processors that support MMX have their L1 cache increased by 16K, on top of the 16K that the original Pentiums had.
Pentium Pro
In 1995, Intel released the Pentium Pro chip, which added a new level of performance to the Pentium processor. The Pentium Pro had all the characteristics of the Pentium processorsuch as a 64-bit data bus and 32-bit registersbut it increased the address bus to 36-bit, which meant that the Pentium Pro could access 64GB of RAM. The speed of the Pentium Pro ranged from 120 MHz to around 200 MHz.
The Pentium Pro added two additional features to its chip that helped it outperform the original Pentiums. First, the Pentium Pro chip was really a two-chip team. One chip (the actual processor) had 16K of L1 cache like the Pentium chip, but the other chip held an extra 256K (or 512K, 1MB, 2MB) of cache memory. Since this cache memory was physically outside of the CPU, it was considered L2 cache.
The second feature, which led to the performance gain of the Pentium Pro, is what is known as dynamic execution. Dynamic execution has three stages: multiple branch prediction, dataflow analysis, and speculative execution.
Multiple branch prediction is the idea that the processor will look ahead and predict a number of instructions that may be needed in the very near future. Dataflow analysis occurs when the processor looks at the instructions it has predicted will be needed next and then assigns them a logical order of execution.
Speculative execution is the actual executing of a given instruction based on the prediction and the
order of execution assigned.
Pentium II
In 1997, Intel produced the Pentium II, which was really just an enhanced Pentium Pro with speeds ranging from 233 MHz to 450 MHz. The Pentium II had a 64-bit data bus, a 36-bit address bus (64GB of RAM), and 64-bit registers.
The Pentium II increased the amount of L1 cache that was integrated into the CPU to 32K, as opposed to 16K. The 32K of L1 cache was still divided into two equal channels: one 16K channel for data and one 16K channel for application code.
Intel has packaged the Pentium II in the Single Edge Contact Connector (SECC) that fits into Slot 1 on the system board. The Single Edge Connector is a module enclosed in a casing or shell with two chips inside, one chip being the processor and the other chip being the 512K of L2 cache. Figure 2-9 shows a Pentium II processor and Slot 1.
SIMD
Another enhancement that accompanied the Pentium II was SIMD (Single Instruction Multiple Data). When I think of SIMD, I like to think of a playroom full of toddlers.
Suppose there are five toddlers in the playroom and that these toddlers are at the entertaining age of twothe age, of course, when the toddlers are preparing for their teen years and they answer no to everything you say. You walk into the playroom and see that the five toddlers have found your box of darts and are throwing them at the walls. You are faced with a choice: you can either walk around to each child and explain why throwing darts at your walls is not a good thing (which means you will have to explain the same thing five different times) or you can have a good scream at the top of your lungs, which means that all the children will stop immediately and listen.
SIMD works on the same basic principle. Suppose, for example, that you have a system running multiple processes at any given time and each process has data that its working with. If the processor has to give out instructions to modify a certain type of data, instead of explaining these instructions to each individual process one after the other (which takes a lot of time), the processor yells, or broadcasts, the instructions
to everyone. Thus, the processor saves time and creates a much more efficient way to communicate information.
Celeron
The Pentium II processor performs very well (and with all that cache memory, it should). Unfortunately, performance comes with a price. If you are not willing to pay that price, Intel has created a chip for you: the Celeron.
The Celeron chip is nothing more than a Pentium II processor with the built-in L2 cache either removed or reduced and then sold at a cheaper price. The first-generation Celeron chip was code-named the Covington. It had no L2 cache memory on it.
The second-generation Celeron was code-named the Mendocino. It contained 128K of L2 integrated into the processor itself. This L2 cache was not another chip sitting beside the processor, like the Pentium II.
Pentium III
The Pentium III processor shares many of the Pentium IIs characteristics. It supports dynamic execution, MMX technology, and has either 256K or 512K of L2 cache. The Pentium III runs at a speed of 450 MHz to 1,000 MHz, or 1 GHz.
The Pentium III chip offers 70 additional instructions that are integrated into the chip, enhancing the users experience with 3D graphic applications. The Pentium III chip also supports a number of low power states to help conserve power when the system is not in use. This processor is designed to run on either a 100 MHz or 133 MHz system board.
Physical size
As the processors increase in functionality, they also increase in size. Table 2-4 lists the dimensions of some of the popular processors. For the exam, you will want to make sure that you take a look at these dimensions.
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Filed Under: Computer Hardware
I thought this might be a discussion of mac on intel! Very good article though =)
[...] are two major players in the market. Intel and AMD. Intel is widely known and highly popular while AMD’s base is growing constantly. I am [...]