 Number 267 - August 2005 |
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| Making Sense of Chip Speeds | |
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by Vinny La Bash, | |
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There is a lot of confusion in the PC marketplace today about the clock speeds of various procesors. Intel, AMD, and Apple all rate their systems differently, and all claim that their chips are better than the others. Pentium 4's, Athlons, and G5 chips all perform the same basic job, but with different designs and specifications. How do we differentiate and choose among them? It can be something like comparing a Yugo with a Ferrari. Either one will get you from Point A to Point B, but a Yugo buyer is vastly different from someone lusting for a Ferrari. While differences among computer chips are not quite that extreme, it pays to know and understand some of the basics before spending any money. If you're looking at Intel, you have a choice between the Pentium 4 and the Celeron chips. Both chips have Level 1 and Level 2 memory caches. Level 1 is the first place the CPU looks when it requests data. If the CPU doesn't find what it wants, it then goes to Level 2 cache. When you examine the specification for the chips, sometimes Level 1 is not mentioned. What you need to know is that this is the fastest memory. All chips implement it in some fashion, and you can't change its speed or size. Don't torture yourself over it. Level 2 cache is a horse of a slightly different color. The size ranges from 256 kilobytes to one megabyte. This is also an extremely fast memory, and the more you have of it, the better. All other things being equal, go for the chip with the most Level 2 cache. It's far better to have a one megabyte Level 2 cache than a chip with a higher clock speed. Celeron chips can be thought of as low power Pentiums, something like the difference between a four and an eight cylinder automobile engine. Level 2 cache in a Celeron ranges from 128 to 256 kilobytes. Celerons are also characterized by slower clock speeds than their Pentium cousins. A Celeron based machine is meant for everyday ho-hum applications. The power hungry should choose Pentium 4 processor machines. All Intel consumer chips are 32-bit with the exception of the Itanium, which is a 64 bit processor. There isn't much 64-bit software on the market today or the foreseeable future. Agonizing between the two doesn't make sense since you won't suffer any performance penalty for buying 32-bit. Advanced Micro Devices' current claim to fame is its top-of-the-line Athlon chips. AMD has been producing 64-bit chips for about a year. Fortunately, they also run today's 32-bit programs. That's a good thing because AMD has made a lot of noise about the superiority of its 64-bit architecture over Intel's 32-bit chips. Athlon's 64-bit chips are indeed technically superior. Regrettably, it's like having an automobile capable of going 200 miles per hour, but the only place you can drive it is in downtown traffic during rush hour. As noted above, there are no 64-bit conventional programs available. |
AMD's clock speeds are lower than Intel, which is no big deal because the architecture of the Athlon chips is more efficient than the Intel design. The result is that Athlon chips give about the same relative performance as their Intel counterparts. AMD chips can handle more instructions per cycle then Intel, which is why their "slower" chips often run faster than some of Intel's higher clock speeds. AMD's nomenclature tends to be at least as confusing as Intel. An Athlon 3000+ has roughly the same capabilities as a Pentium 4 3.0 GHz. The 64-bit Athlon comes with either 512 kilobytes or one megabyte L2 cache. The Athlon XP, a 32-bit chip, has 512 KB of L2 cache. AMD also makes an economy chip, the Sempron that competes with the Celeron. It has 256 KB of L2 cache, and is a 32-bit chip. If your head isn't spinning by now, let's take a peek at Apple's G5 chips, manufactured by IBM. Both Power Macs and iMacs use the G5 chip. Some run at speeds well under 2 GHz. Like AMD, Apple thinks that instructions per cycle are more important than clock speed. If you have interest in the iMac, test it in the showroom. After your initial disappointment, try the iMac's more powerful siblings, the Power Macs. They all have dual processors, and they are fast. The cheapest is $2000 without a monitor, so they're not cheap. All G5 chips have 512 KB of L2 cache. Summary: AMD or Intel will give you a good combination of power and speed. Don't buy top of the line unless you enjoy buying overpriced goods or you have an application that really needs the extra power. Buy one or two levels down to get the best price combined with good performance. 64-bit chips are superior technology, but there is no software today that can make use of their advanced design. Apple's Power Macs are very powerful, but they're also very costly compared to Intel or AMD. If you don't mind the expense, you won't be sorry with a Mac. The iMacs are underpowered, but will make a good choice as a second machine. The same advice applies to Apple's 64-bit chips. The 64-bit technology is a waste. Another possible complication is an industry rumor that Apple is seriously considering switching from IBM chips to Intel chips. The Celeron and Sempron chips are good choices if you have a tight budget. Don't look for blazing speed. There is a reason they sell at bargain prices. Copyright 2005. This article is from the July 2005 issue of the Sarasota PC Monitor, the official monthly publication of the Sarasota Personal Computer Users Group, Inc., P.O. Box 15889, Sarasota, FL 34277-1889. Permission to reprint is granted only to other non-profit computer user groups, provided proper credit is given to the author and our publication. |
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Number 267 - August 2005
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