The Pentium IV Dissected

An AC pointed sent us this: "In this extremely well written and technical article, the author points out the various mistakes that Intel made with the production of the Pentium IV, the fact that Intel and other manufacturers have been misleading customers about the performance of the Pentium IV, and the amount of work that will be pushed onto software developers backs to get a piece of software to run at a reasonable speed." Beginning section readable by anybody; by the end you need to know a little more assembly language than is healthy for anyone, but excellent overall. For a Cliff's Notes version of the above, try this NYTimes article discussing the chip in non-technical terms. My guess is that most computer buyers will continue to compare only clock speeds, however.

Comments

Bad execution, not architecture

[alexjohns]

I think a lot of people need to take a chill pill. The guy's not saying Intel sucks, period. He's saying that the P4, in its present form, is not a good value for your money. That's it. That's all he's saying.

He didn't say that the overall architecture is bad. He didn't say that the P4 will lead to bad designs in the future. He said that some of the choices for the present P4 configuration are bad and that people would be better served by spending their money elsewhere. If people buy Intel chips no matter what the actual price to value ratio is, then Intel has won and the consumer has lost.

The author gives very good explanations of the limitations of the present incarnation of the P4. He also explains what he thinks needs to be fixed. With all those fixes, the P4, in a few years, will likely be a really good chip. The design isn't beyond repair, it's just flawed.

I remember the 486SX clearly - and how my father was duped by the hype. The same thing's happening here. Also, if Intel really believed the P4 was its best chip, why are the colored guys on TV hyping the P3 like there's no tomorrow? (No, that's not a racist remark. If you've seen the ad, you know what I mean.)

The bigger problem is that, even though you can get around the limitations of the P4 chip by writing a really smart compiler, the P3's and below will be around for years, so you won't necessarily be using the optimization settings in generic code. You'll likely see 'Word 2005 for the P4' and 'Word 2005 for the P3 and below', although there's nothing preventing them from being on the same DVD and the installer choosing the right version.

If you can get past some of the strong language in the article (Intel engineers are stupid; boycott Intel; etc.) you can see that he's not anti-Intel per se. He's anti-Intel's marketing guys, who seem to be running the company at the moment. The decisions made in the present P4 incarnation have to be marketing's - no other explanation holds water. You can't design the next generation chip and then deliberateley cripple it. That's like having a son and then cutting off his foot to see how he gets along in the real world. I doubt engineers had much to say in the present P4 configuration.

The author provides pretty convincing proof that the best value for your money is an Athlon system, right now. I haven't seen anyone here able to refute that statement. It's the same conclusion that a couple of other people have reached. From all I've read over the past few months, I have to agree.

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Two things

[Lover's Arrival, The]

First, I'd be extremely interested to see what this guys credentials are - its interesting to see him take the entire Intel CPU design team to task over this.

Secondly, I thought the entire point of the Pentium IV is that it is focused on different areas to the PIII and others. Specifically, it is designed for a media rich environment, and was designed with the future in mind. I would guess (bear in mind, I don't have any credentials) that we won't see the best of the PIV until a year or two down the line, when compilers are properly optimised for it and people start programming with its architecture in mind. Until then, I fear we are making unfair comparisons. Just my guess!

Pentium IV is still good, but we'll have to wait

[ZanshinWedge]

The Pentium IV was designed and conceived to be somewhat of a different beast than the current cpu lineup. Not as different as IA-64 and all that. The current processor designs are reaching their limits in terms of speed and won't be able to go much faster than where they are now. The P4 is a different beast. It is primarily designed to simply allow for monstrously high clock frequencies. Now, making such a switch of technology and design is always difficult and combined with some of Intel's other problems (like the stupid contract with rambus, which is really hurting them badly all around) makes for a a rough road. This first generation of P4's quite plainly isn't much higher clocked than other chips (at most 50%) and even then it doesn't stack up well, partly due to chipset and memory problems though, and it is a huge chip (physically) which costs money. Combined with the normal amount of bugs and blunders in a new product and you get less than stellar performance.

However, that's not the whole story. Intel has always introduced new chips, tweaked them, put production in gear, lowered the cost, then inundated the public with high quality, high performance, low cost processors. I doubt the P4 will be much difference. With the process change (to 0.13 micron I believe) for the P4 comes, combined with the normal bug fixes, combined with better memory support (such as DDR SDRAM), combined with much higher clock speeds (we're talking over 2 GHz), combined with major production volumes and lower prices, the result will be a screaming fast processor that will be hard to beat. The P4's main advantage (and essentially it's entire raison d'etre) is that it has a whopping 20 stage pipeline. That means one thing, you can shove gigahertz down it's throat like you can't do to any other processor. Sure the P4 may not be as "tight" and efficient as some of the other processors out now (which is why it's foolish to be an early adopter), but what it lacks in effectiveness it will eventually make up for in raw cycles. Right now (with all of the P4's flaws, including those that can be fixed, mind you) the P4 runs at maybe 80% of what the idealized speed of a PIII or Athlon would be at the same clock speed, but they expect the P4 to hit 2GHz by Q3 '01 which means you need around a 1.6 GHz proc. of the old style to keep up with it. And this assumes that some of the weak points of the P4 (most importantly, the horrendous memory system forced on it by the Rambus contract) remain, which won't be the case.

I'm not saying the P4 will blow everything out of the water next year (it won't), but it will be fully mature and it will be leading the pack and will be very difficult to compete with.

Re:Sorry, never made it past the opening paragraph

[mav[LAG]]

Pity - because it's well written, technically sound and has the kind of insight you only get from years of progamming in assembly language on different generations of processors. It's not all anti-Intel. He also gives credit where credit is due - the design of the 386 and 486 chips for instance.

A good editor would have removed the BOYCOTT ALL INTEL stuff or at least moved it down a bit. But I feel for the author here: he paid $4000 for a system which isn't as good as a (much) cheaper Athlon.

Crusoe watchers take note: there's a nice little summary of the Crusoe's performance and why he's very impressed with that CPU's architecture. That summary alone is worth reading.

A new scapegoat is always necessary

[Fervent]

Out of curiousity, does anybody else notice the underlying psychology of this, and many other news posts on Slashdot? I'll put it simply: the tech community looks like it's always is looking for someone to blame.

No the PIV is not a great chip. Hell, it's not even a good chip. But once AMD got onto the scene, it looked like we were itching and scratching to find a way to go against the "bigger company" (Intel, Microsoft, and now RedHat notwithstanding). In 6 months, we'll have a whole new "adversary" to rile up the tech community.

Enough is enough. Yes, the PIV has flaws. Every chip has flaws. You pay extra to get just a smidgen more performance, but that's why AMD is referred to as the "price/performance leader".

However, if we don't root for Intel, and AMD suddenly takes over, who won't put their money down that we will go against AMD? I say support both (I use the same mentality in buying a Sega Dreamcast/PS2; boxed distros of Linux and Windows 2000). Without competition on both sides, even "the Man's", there will be no forward progress.