Slash, "quantispeed", like many other marketing names applied to PC components means absolutely nothing.
(Other examples are "netburst", "pentium", "hyperpipelined", "Athlon", "Duron", "Celeron".) None of these are real words. They use parts of real words to give you the impression that they mean something.
Athlon is similar to the latin for "performing unit" and Duron roughly translates as "lasting unit". "Netburst" is an Intel marketing term for certain parts of the P4 core architecture. "Quantispeed" is the AMD equivilant of that term. Marketing departments probably consume large amounts of pizza and beer, combined with a lack of sleep, to get themselves into the right frame of mind to come up with new totally meaningless but cool sounding words.
You aren't totally wrong with what you said above though, it is true that at the same clockspeed an Athlon will outperform a Pentium 4. Even though you know this, the general computer buying public often chooses a computer based ONLY on the clockspeed they see on the features list. Why an Athlon is able to do this is far beyond the scope of this post, and would require hundreds of pages on CPU design theory and architechural details of both processors.
I've seen a lot of analogies around which try to explain this in a somewhat meaningful way, but picture it this way: (I hope you like cars...
) A 454 Chevy V8 and a 350 Chevy V8 are both automobile engines. They both do the same job, and both interface with the same basic components (radiator, transmission, etc), but one is a "big block" and one is a "small block" engine. At the same RPM, which one is more "powerful"? What whould happen if the only rating system you had to compare the two engines was RPM though? Obviously the small block 350 can achieve higher RPMs than the 454 can, but that's not a totally valid comparison to decide which engine would be best in your truck.
I realize this is a silly way to try to describe this to you, obviously CPUs are not car engines, but it's not a totally inaccurate way of describing what's going on here. AMD's Athlon would be the 454 big block engine in the above example and the Intel P4 would be the 350. To explain to the public how the Athlon could perform equally with a P4, even though their clockspeeds were not the same, AMD invented a marketing term called "quantispeed". Basically they want you to think that the Athlon is somehow "turbocharged" and gets more work done per clock cycle. This is, in general, a true statement.
The Athlon is a kind of like a "brute force" type of processor. It can handle a higher number of instructions at once than the P4, and it's floating point math (FPU) unit is far superior to that of the Pentium 4. (The FPU is used for high precision mathematical operations.) Applications that make heavy use of the FPU almost always show the Athlon coming out ahead of the P4 in those tests. Most scientific, engineering, and Direct X games (and flight sims in particular) make heavy use of the FPU.
Compared to the Athlon, the P4 was designed to be capable of very high clockspeeds, but at the expense of how much it could process per clock. I don't know exactly why Intel chose this approch when designing the P4, but it doesn't hurt that it makes it very easy to scale up in clockspeed with much less effort than AMD requires to increase the Athlon's clockspeed. This ensures a fairly long lifetime of this design for future Intel processors. You may not know, but Intel's previous desktop processor design, the P6 core, was used under multiple names with only some fairly minor changes over its lifetime. (The P6, in all its various forms, was the heart of the Pentium Pro, Pentium 2, Pentium 3, and Celeron. These processors spanned from 1995 until 2002, as the Celeron is still based on this core.) I personally believe Intel wanted the successor to the P6 core to also be capable of being adapted and modified to serve as the heart of Intel processors for years. In that, they succeeded.
I don't want to mislead you and let you get the impression that the P4 is a "bad" performing design, remember that since Intel can easily boost up the clockspeeds they can match the performance of the Athlon at its lower clockspeeds to win over the enthusiast market and wow over the general public when if they were to see the huge difference between the clockspeeds the P4 and Athlon run at. When Intel released the P4 2.4 Ghz, that was the first time in over a year and a half that their top of the line processor edged out the top of the line Athlon for first place. The Athlon XP 2100+ still definately wins the "bang for the buck" race though.
AMD response, to keep from losing the business of the general (uneducated in computers) public was to invent the term "quantispeed" to describe how, for example, a 1467 Mhz Athlon can outperform a 1700 Mhz Pentium 4.
The CPU business changes very quickly as to which is the top performing CPU at a particular moment. In just a few days (May 2, from leaked information) AMD will be releasing a new Athlon XP core at higher clockspeeds. Expect Intel to respond soon after with a 2.533 Ghz P4 to match AMD.
At the end of this year, AMD will be releasing it's sucessor to the Athlon XP, or more exact 2 replacements. One will likely sell under the marketing name Athlon XP-64 and the other was just named the AMD Opteron processor. The lower performance Athlon XP-64 is supposed to launch at a true clockspeed of 2 Ghz, but will carry at least an XP 3400+ rating, or the equal of a 3.4 GHz P4 Northwood. The Opteron will be even more powerful, but it will be out of the price range for the average consumer on launch. Intel has a new P4 core (actually 2) which they plan to release on mid-2003 to respond to AMD. It's a never ending cycle for the next couple years at least.
I hope that's helped you some.
Unfortunately I don't know anything about ABS computers. (I build my own computers.)
