Beyond MHz: It's the Whole System that Counts

Evan Kleiman - 2002.12.04

If you've read any of the Mac performance and benchmarking sites, such as Bare Feats and Accelerate Your Mac, you've probably seen an example where a 500 MHz G4 system with some upgrades outperforms a stock 600 MHz G4 computer.

Why does this occur? The 600 MHz processor in our hypothetical example runs much faster than the 500 MHz one, so it should win. All that matters is megahertz, right?

Well, no.

"Megahertz-myth" is a buzzword that has been thrown around for a while. Many people buy a computer because it has a 1.2 GHz processor (or something of the like). These uninformed consumers are the reason most computer companies sell their computers so cheaply.

Conversely, people who do know are the reason Apple sells their computers for so much compared with other personal computer makers.

The bottom line is that in today's ultra-fast computing world, megahertz means almost nothing. But what does mean something when buying a computer and comparing it to others?

Bits and Pieces

Like cars, houses, and many other things, computers are made up of several different subsystems or devices. The components in your computer operate together, often running no faster then the slowest part. This brings us to our next buzzword: bottlenecks. A bottleneck occurs many ways in a computer. But, either way, it's all the same. You could have the fastest dual G4 Apple makes, the newest software, and a great hard drive, but if you can't get the information on the screen fast enough because you have a slow video card, then much of that power is wasted.

This is part of the reason Dell and Gateway can sell their computers so cheaply. 1 GHz and faster Pentium and Celeron processors can be had rather cheap, and that makes the core of a cheap computer when a cheap video card helps offset the cost of a "high speed" CPU.

Most buyers don't know about bottlenecks. They'll see a computer with a fast processor and assume that it's fast. I've often seen these bargain-basement brands, such as eMachines, sel a "fast" computer with an excruciatingly slow hard drive or other component. They can sell these computers so cheap because, while the processor might cost them a little bit more than average to produce or buy, the cheap components lower the overall price of the system.

However, to the buyer it still looks like a great, fast deal.

The last selling point that computer manufacturers use to market their "unbalanced" products is memory. A lot of companies will sell their computers with huge chunks of memory. However, the fact of the matter is that unless you're doing some sort of high-end gaming or desktop publishing, anything over 256 MB is probably more than you need. Of course, with vendors promising great performance from some computer with 512 MB or more for a cheap price, the offers seem unbeatable - but don't be fooled. Memory is one of the cheapest components in a computer, so companies can sell computers with far more than you'll ever need. It makes the computer more appealing to everyone except the true computer expert.

Editor's note: Too little memory can create bottlenecks, forcing the computer to use the hard drive as virtual memory and slowing overall performance. There is no penalty for having too much memory beyond the cost of the memory, but there can be a significant performance penalty for having too little. The more programs you run at once and the newer your operating system, the more RAM you need. dk

Memory confusion is also found in video cards. There are very many high-end video cards that are placed into a computer. Often times, companies will sell this as a "gaming platform," yet it will have a slow hard drive and barely enough memory to play Doom I. While these ultra-fast 128 MB video cards are great for gaming, most low-end Mac users don't play the newest high-end games, so they don't really need this kind of card. Even when running OS X 10.2's Quartz Extreme, 128 is more than you'll ever utilize.

This brings up another topic: misnaming. Misnomers are commonplace in today's computing world. For instance, I have a Rage 128 video card in my Blue and White G3. This 128 can mean many things, such as video memory, bus speed, etc. But, this 128 seems to have no bearing on any of these aspects.

This is also true with the AMD Athlon 2100+ processor. Its clock speed is not 2100 MHz. It's called this because the 1.73 GHz CPU is "as fast as" a 2.1 GHz processor. Sounds like another way to fool buyers to me.

Editor's note: On the flip side, the Intel Pentium 4 is roughly 25% less efficient than the older Pentium III at the same clock speed, but because of the ease of marketing MHz instead of overall performance, Intel is making out like a bandit selling 2-3 GHz CPUs. dk

If these companies are emphasizing the wrong things when marketing their computers, what should we buy? We can only hope for more honesty and better balancing of premade computers from these vendors in the future.

Until then, you had better rely on computer websites that thoroughly test the whole computer. One component doesn't make a huge difference. All the components in a computer work as a team.

The truly fast computer has a balance of components, and while they're not necessarily the fastest individual components, they can work faster than a computer designed around a single very fast component.