Intel's Pentium 4 E: Prescott Arrives with Luggage
by Anand Lal Shimpi & Derek Wilson on February 1, 2004 3:06 PM EST- Posted in
- CPUs
Final Words
If you’re looking for nothing more than a purchasing decision let’s put it simply: if you’re not an overclocker, do not buy any Prescott where there is an equivalently clocked Northwood available. This means that the 2.80E, 3.00E, 3.20E are all off-limits, you will end up with a CPU that is no faster than a Northwood and in most cases slower. If you are buying a Pentium 4 today, take advantage of the fact that vendors will want to get rid of their Northwood based parts and grab one of them.
Overclockers may want to pick up a Prescott to experiment with ~4GHz overclocks – it will be easier on Prescott than it is on Northwood. And once you get beyond currently available Northwood speeds you will have a CPU that is just as fast if not faster, depending on how high you go.
When you include AMD in the picture, the recommendation hasn’t changed since the Athlon 64 was introduced. If you find yourself using Microsoft Office for most of your tasks and if you’re a gamer the decision is clear: the Athlon 64 is for you. The Pentium 4 continues to hold advantages in content creation applications, 3D rendering and media encoding; if we just described how you use your computer then the Pentium 4 is for you, but the stipulation about Northwood vs. Prescott from above still applies.
The Pentium 4 Extreme Edition at 3.4GHz does provide an impressive show, but at a street price of over $1100 it is tough recommending it to anyone other than Gates himself.
With the recommendations out of the way, now let’s look at Prescott from a purely microarchitectural perspective.
Given that we’re at the very beginning of the 90nm ramp and we are already within reach of 4GHz, it isn’t too far fetched that Prescott will reach 5GHz if necessary next year. From an architecture perspective, it is impressive that Prescott remains in the same performance league as Northwood despite the fact that it has a 55% longer pipeline.
What we have seen here today does not bode well for the forthcoming Prescott based Celerons. With a 31 stage pipeline and 1/4 the cache size of the P4 Prescott, it doesn’t look like Intel will be able to improve Celeron performance anytime soon. We will keep a close eye on the value segment as it is an area where AMD could stand to take serious control of the market.
The performance of Prescott today is nothing to write home about, and given the extensive lengthening of the pipeline it’s honestly a surprise that we’re not castrating Intel for performance at this point. Prescott is however a promise of performance to come; much like the Willamette and even Northwood cores were relatively unimpressive at first, they blossomed into much sought-after CPUs like the Pentium 4 2.4C. The move to 90nm and a longer pipeline will undoubtedly mean more fun for the overclocking community, especially once production ramps up on Prescott.
Just as was the case with the very first Pentium 4s, Prescott needs higher clock speeds to spread its wings - our data on the previous page begins to confirm this. To put it bluntly: Prescott becomes interesting after 3.6GHz; in other words, after it has completely left Northwood’s clock speeds behind.
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sprockkets - Monday, February 2, 2004 - link
Hmmm... on Intel's website on the new processor news: "Thermal Monitoring: Allows motherboards to be cost-effectively designed to expected application power usages rather than theoretical maximums."Not sure what it means. I'm thinking clock throttling so that if your particular chip is hotter than it should be it will run on under engineered motherboards/coolers.
This chip dissipates around the same heat as Northwoods clock for clock! And of course, Intel style is wait 6-12, then the new stuff will actually be good. Still, is it really that important to increase performance so much that heat becomes an issue? I.E., will Dell be able to make the cooling whisper quiet? They can with the processor sitting at 80-90c, but now that with normal cooling it's almost there, now what will they do? Why can't we just have new processors that run so cool that we can just use heatsinks without fans? Oh well.
Novaoblivion - Monday, February 2, 2004 - link
Great article :) I found it very interesting I dont think I'll be buying a prescott till they hit about 4Ghz. My 2.4C is nice and fast for now.CRAMITPAL - Monday, February 2, 2004 - link
http://www.theinquirer.net/?article=13927
http://www.theinquirer.net/?article=13947
johnsonx - Monday, February 2, 2004 - link
To Vanners, #38:"if you halve the time for a stage in the pipeline and double the number of stages. Yes this means you can run at 2GHz instead of 1GHz but the reality is you're still taking 5ns to complete the pipe."
Yes and no... In the example, you're right that a single instruction takes the same 5ns to complete. But you're not just executing a single instruction... rather, thousands to millions! The 10 stage pipe has twice as many instructions in flight as the 5 stage pipe. Therefore in the example, you get one result out of the 5-stage/1Ghz cpu every 1ns, but TWO results out of the 10-stage/2Ghz cpu in the same 1ns... twice as many.
What I find interesting is that as pipelines get longer and longer, we might have to start talking about Instruction Latency: the number of clocks and ns between the time an instruction goes in and when the result comes out. It'll never be anything a human could notice directly, but it might come into play in high-performance realtime apps that deal with input from the outside world, and have to produce synchronized output. Any CPU calculates somewhat "back-in-time" as instructions fly down the pipe... right now, a Prescott calculates about twice as far behind 'reality' as an A64 does. I don't know if there is any realworld application where this really could make a difference, or if there ever will be, but it's interesting to ponder, particularly if the pipeline lengths of Intel vs. AMD continue to diverge.
cliffa3 - Monday, February 2, 2004 - link
i don't see how a 4+GHz prescott will match up with intel's new pico BTX form factor...with that much heat (using air cooling), you need to keep a safe zone around the proc unless you like your RAM DDR+BBQ.I'd have to say that a lot of enthusiasts are younger and live in limited space conditions...might work well for people up north who don't want to run the heater, but as for me in texas, i have all the cool air pumping in to my bedroom and it still takes a lot to keep it cool. Can you imagine a university or corporation having a room full of those?..if they think about that, then it's no bueno for DELL and others as well.
I'd also have to agree with the others about the heat/power being a major part of the article that was left out...otherwise a tremendous read, thanks for all the effort that goes into these.
tfranzese - Monday, February 2, 2004 - link
But - I need to add - the correction was needed and is welcome. Not trying to pick a bone with the editors.tfranzese - Monday, February 2, 2004 - link
#55, you read what I read. I'll vouch for you.Icewind - Monday, February 2, 2004 - link
#55Better go back to sleep me thinks :)
Spearhawk - Monday, February 2, 2004 - link
Is it just me (who was extremely tired yesterday) or has the 101 on pipeline part changed since the article was put up?I seem to rememeber reading someting about how a 5 staged CPU at 1 Ghz should be exactly as fast as a 2 GHz CPU with 10 stages (all else being equal of course) and that the secret of geting any profit out of going to more stages was to make sure that it couldn't only scale to 2 Ghz but to 3 Ghz or more.
Icewind - Monday, February 2, 2004 - link
I think shuttle owners are SOL with prescott.