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
Prescott's Little Secret
In learning about Prescott and trying to understand just why Intel did what they did, we came to realization: not only is Prescott designed to be ramped in speed, but there was something else hiding under the surface.
When overclocking a processor, we can expect a kind of linear trend in performance. As Northwood's speed increases, its performance increases. The same is true for Prescott , but what is important to look at is increase in performance compared to increase in clock speed.
Prescott 's enhancements actually give it a steeper increase in performance per increase in clock. Not only can Prescott be clocked higher than Northwood, but as its clock speed is increased, it will start to outperform similarly clocked Northwood CPUs.
We can even see this trend apparent in our limited 3 clock speed tests. Most of the time, the 2.8GHz Northwood outperforms the 2.8GHz Prescott, but the percentage by which Prescott is outperformed decreases as clock speed increases, meaning that the performance delta is significantly less at 3.2GHz.
Business Winstone 2004
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
1.48% |
3.00GHz |
0.00% |
3.20GHz |
0.46% |
Content Creation Winstone 2004
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-3.57% |
3.00GHz |
-5.67% |
3.20GHz |
-5.43% |
SYSMark 2004
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
1.19% |
3.00GHz |
2.27% |
3.20GHz |
2.70% |
SYSMark was one of the only applications to show a positive performance improvement for Prescott, and we see that with clock speed that advantage continues to grow over Northwood. Keep on reading, it gets even more interesting...
Aquamark - CPU Score
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-2.87% |
3.00GHz |
-2.47% |
3.20GHz |
-0.84% |
Halo
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-0.18% |
3.00GHz |
-0.18% |
3.20GHz |
0.00% |
GunMetal
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-0.29% |
3.00GHz |
-0.58% |
3.20GHz |
-0.29% |
UT2003 - Flyby
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-2.62% |
3.00GHz |
-1.46% |
3.20GHz |
-0.86% |
Clock speed goes up, Prescott performs more like Northwood.
UT2003 - Botmatch
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-3.55% |
3.00GHz |
-3.09% |
3.20GHz |
-2.05% |
Warcraft 3
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
1.96% |
3.00GHz |
1.12% |
3.20GHz |
0.72% |
We continue to see that as clock speed increases, the gap between Prescott and Northwood decreases as well.
Quake III Arena
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-1.33% |
3.00GHz |
-0.49% |
3.20GHz |
1.28% |
Quake becomes the textbook case of what should happen to Prescott performance as clock speed increases; although initially it is slightly slower than Northwood at 2.80GHz, by the time we reach 3.2GHz Prescott holds an advantage over a 3.2GHz Northwood. This is exactly the trend we expect to see over time, especially once we get close to 4GHz.
Jedi Knight: Jedi Academy
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-7.63% |
3.00GHz |
-6.85% |
3.20GHz |
-7.04% |
Wolfeinstein: Enemy Territory
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-5.53% |
3.00GHz |
-4.94% |
3.20GHz |
-3.79% |
DivX Encoding
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-1.30% |
3.00GHz |
-0.61% |
3.20GHz |
-0.38% |
3dsmax R5
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-9% |
3.00GHz |
|
3.20GHz |
-9% |
There will be some scenarios that do not work in Prescott's favor, and in those cases Northwood will still remain faster.
Lightwave 7.5
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-7.7% |
3.00GHz |
|
3.20GHz |
-6.8% |
Although to a much lesser degree, we are seeing the same sort of scaling with clock speed in applications like Lightwave. It looks like our theory about Prescott's performance is correct.
Visual Studio Compile Test
| Percentage Increase in Performance from Northwood to Prescott | |
|---|---|
2.80GHz |
-8.2% |
3.00GHz |
|
3.20GHz |
-3.8% |
Much like Quake, our compile test is another perfect example of what clock scaling will do to the Northwood/Prescott gap. As the clock speed goes up, the performance delta decreases.
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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.