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In the Forums... |
Posted: July 17, 2001 Written by: Tuan "Solace" Nguyen The Processor There isn’t anything new about the 1.8GHz Pentium 4 that wasn’t already seen in slower Pentium 4’s before it. All specifications remain the same with the exception of speed. Here’s a brief rundown of what comes under the hood. 1.8GHz 0.18 micron fabrication process 427 PGA Socket compatible NetBurst architecture 16KB Trace Cache 256KB Level 2 Cache There’s one entry in the list above that’s a real damper on the Pentium 4’s overall speed and that’s the 16KB Trace Cache. You can think of this cache as the L1 cache of the Pentium 4. If we take a quick history listen, we learn that the Pentium 3 has 32KB of L1 cache. The rule in microprocessor design states that the faster the processor is, the larger its cache must be. This is because there must be enough information at hand at all times considering that the rest of the system is far slower than the processor itself. The fastest component next to the processor core itself is the L1 cache. If the processor cannot fetch the instructions it needs in L1, then it will move to L2 cache. If L2 doesn’t have what it needs then it will look into main memory and finally the hard drive. Since the Pentium is running at 1.8GHz, it would have been much more efficient for it to have a larger L1 cache. In comparison, AMD’s Athlon processor has 128KB of L1 cache, 18 times as large as the Pentium 4’s. Another feature the Pentium 4 sorely lacks is the ability to optimize instruction sequences, that is, the flow of instructions when it is decoding them. The Athlon has 3 instruction decoder units whereas the Pentium 4 only has 1. The job of instruction optimization is now in the hands of compilers. So not only do programmers have to optimize their code to take advantage of the Pentium 4, their compilers must also be redesigned! Now granted Intel is providing its compilers to developers, but not every company will redesign their compilers to fit nicely with the Pentium 4’s grand scheme of things.  Above is a picture of the Pentium 4 1.8GHz. The one you’re looking at however is an engineering sample and the retail processor will not look like that. Instead the text etching on the metal plate will be different and will have the name “Pentium 4” instead of “Intel Confidential”. The metal cover on top of the core acts as a heat spreader and also protects the fragile core from chipping and breaking should you improperly install the heatsink. AMD should listen to the calls of its customers and implement something similar to what Intel has done. Not only will it ease the installation fear for users, it will protect their investment. Besides, that’s what a company that cares for its customers should do.  Initially a copper/aluminum heatsink was included with the Pentium 4 but Intel has recently switched to an all aluminum heatsink and gone back to using high quality Sanyo Denki fans. These fans are one of the quietest fans that also perform well. You’ll probably have difficulty finding these fans in the retail chain though. The Pentium 4’s architecture supposedly lets it scale well with clock speed increases so let’s take a look at how the 1.8GHz performs compared to its slower siblings. |
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