The XP series of CPUs are sold under a rating system, rather than their clockspeed.
The 1700+ model actually runs at a clockspeed of 1.47 Ghz. Now that I've said that, read on, because there are some points that need made:
1. The XP 1700+ actually performs overall a bit better than a 2 Ghz P4 of the older "Willamette" design, and roughly better than a conjectural 1.7 Ghz "Northwood" core P4. Intel does not actually make a P4 1.7 Ghz with the Northwood core, those are at 1.6, 1.8, 2.0, 2.2, and 2.4 Ghz. You can tell a northwood from a willamette by the socket (478 vs 423 pins) and Intel uses an 'A' in the name for the 2.0 Ghz and below. All P4s at > 2.2 Ghz are northwoods. All Athlon processors perform much better than P4s at the same clockspeeds, AMD accounts for this by assigning a model number to them. You really should look at places like
http://www.anandtech.com to get a true idea on how these CPUs stack up. The model rating uses a number of tests, and IMO is actually very conservative, but there are some areas where an Athlon will crush the P4, and some areas where the P4 is better than the Athlon.
2. The current Athlon XPs, which uses the Palomino core, vs the older Thunderbird core of the previous Athlon. Compared to Thunderbird (tbird), the Palomino core incorporates a couple improvements to the CPU itself which mean it performs a bit better than a Thunderbird would at the same clockspeed. Without detailing out exactly what they do (which would be a little beyond the scope of this post), these are support for SSE instructions (Intel created these, the P3 was the first CPU to use them), hardware prefetch, optimized die layout (reduces heat), larger TLB buffers (transistion lookaside), and a couple other minor things. The big one here is SSE instruction support, this allows the Athlon XP to take advantage of Intel P3 optimized programs AND programs which are optimized for AMDs own 3dnow instruction set. (Note, if you switch from a Tbird or Duron < 1GHz, you need to reinstall Windows to enable this function.) All told, a Palomino core Athlon XP will perform about 10 - 20% better than a tbird core Athlon at the same clockspeed. AMD invented a marketing name for these additions, calling it "Quantispeed." (Intel did the same for the P4, calling it "netburst" which btw has nothing to do with the internet and will not 'speed up your internet' by any amount whatsoever. The processor has ABSOLUTELY zero effect on your connection speed. I don't really know why Intel would want to confuse uninformed buyers with this.)
(Slash, I'm not sure what you mean by that "4 266 Mhz bus lines" thing. I'm pretty sure what you are confused with is what is known as the FSB (front side bus), which links the CPU to the motherboard chipset. The later tbird Athlons and all Athlon XPs use a 133 Mhz bus, but at double data rate (DDR), which is the equivilant of having a 266 Mhz bus.)
For the record, the XP 1500 + runs at a true clockspeed of 1333 Mhz, the 1600+ at 1400 Mhz, the 1700 + at 1466 Mhz, the 1800 + at 1533 Mhz, the 1900 + at 1600 Mhz, the 2000+ at 1666 Mhz, the 2100+ at 1733 Mhz. Can you see the pattern, there is a 66.67 Mhz true clockspeed difference between them. If you want to get really general with this rating system, you can gather that an Athlon would be around 33 % more powerful than a P4 Northwood at the same true clockspeed. That's making some really basic generalizations on typical PC usage and is full of loopholes, but it's not a bad assumption.
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I hope that answered some questions.
bloom25 - Electrical Engineer specializing in digital and analog circuit design. (Digital logic runs over into CPU design principles.)
