Intel Pentium 4 6xx and 3.73EE: Favoring Features Over Performance
by Anand Lal Shimpi & Derek Wilson on February 21, 2005 6:15 AM EST- Posted in
- CPUs
Introduction
Just last week, we saw the first tests of Intel's newest Xeon processor formerly codenamed Irwindale. The major improvement Irwindale offers over Nocona is an extra 1MB of L2 cache. Our dual processor server configuration showed the 2MB cache of the Irwindale based Xeon offering a significant improvement under certain workloads. In a shared front side bus dual processor configuration, the improved cache hit rate of the 2MB Xeon helps to keep the NetBurst architecture from getting tangled up in the length of its pipeline when working with lots of data. As an added bonus, the impact of sharing a front side bus is softened when processors find more of the data they are looking for locally. On the consumer side, Intel's 600 series doesn't have to deal with shared busses or server sized workloads. Will the 2MB L2 cache still come through and offer a significant performance improvement?
The short answer is that consumer applications running on a single processor system don't see the same kind of benefit from a 2MB L2 as do server workloads running on a DP Xeon. There are areas where performance is affected, but this time around Intel is again refining and broadening its platform rather than simply scaling up speed and power. Let's take a look at the new offerings introduced this week.
First off we've got the new Pentium 4 600 series, launched in four models:
| Model | Clock Speed | Socket | L2 Cache | FSB |
| Intel Pentium 4 660 | 3.6GHz | LGA-775 | 2MB | 800MHz |
| Intel Pentium 4 650 | 3.4GHz | LGA-775 | 2MB | 800MHz |
| Intel Pentium 4 640 | 3.2GHz | LGA-775 | 2MB | 800MHz |
| Intel Pentium 4 630 | 3.0GHz | LGA-775 | 2MB | 800MHz |
What advantage does the Pentium 4 600 offer over the 500 series? The main features are a 2MB L2 cache, Enhanced Intel SpeedStep Technology (EIST) and EM64T support (Intel's version of AMD's x86-64). The Pentium 4 600 is still built on the same 90nm process as the Pentium 4 500, it's just got twice the cache (which we'll talk about later). Features like EIST and EM64T support were always there on previous 90nm Pentium 4s, they were simply not enabled.
Currently the 500 and 600 series chips are priced to coexist with one another, first let's have a look at what Intel's official prices are:
| Pentium 4 500 Series | Pentium 4 600 Series | |
| 3.8GHz (Model _70) | $637 | Q2 Release |
| 3.6GHz (Model _60) | $417 | $605 |
| 3.4GHz (Model _50) | $278 | $401 |
| 3.2GHz (Model _40) | $218 | $273 |
| 3.0GHz (Model _30) | $178 | $224 |
Then let's take a look at street prices for the chips using our RealTime Pricing Engine:
| Pentium 4 500 Series (street price) | Pentium 4 600 Series (street price) | |
| 3.8GHz (Model _70) | $690 | Q2 Release |
| 3.6GHz (Model _60) | $425 | $635 |
| 3.4GHz (Model _50) | $279 | $429 |
| 3.2GHz (Model _40) | $231 | $295 |
| 3.0GHz (Model _30) | $184 | $257 |
The other thing to note is that the 500 series still holds the clock speed crown, with the 570J running at 3.8GHz, while the fastest 600 series is a 3.6GHz Pentium 4 660. What we're seeing here is another example of Intel's move away from clock speeds as the only "improvements" from chip to chip. We will however see a 3.8GHz Pentium 4 670 in Q2 of this year.
Intel's next announcement is the move to a new 90nm core for the Pentium 4 Extreme Edition. Until now, all EE chips have been based off of the old 130nm Northwood core, but with the move up to 3.73GHz the Extreme Edition actually uses the same 90nm core as the new Pentium 4 600 series.
Giving up its 2MB L3 cache in favor of a lower latency 2MB L2 cache, the new Extreme Edition only offers two benefits over the regular Pentium 4 600 series CPUs: clock speed and 1066MHz FSB support. Priced at $999, the new Extreme Edition is priced in accordance with its name, as all of its predecessors have.
The new core, shared by both the Pentium 4 600 and the new Extreme Edition chips, is still built on the same 90nm process as the original Prescott, but thanks to the larger cache weighs in at 169 million transistors, an increase of 44 million (or 35%) over the original Prescott 1M core.
There's a decent amount to discuss with this new core, so let's start at the biggest change - the cache.
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KingofL337 - Tuesday, February 22, 2005 - link
Why would anyone buy a P4 for EMT64? When AMD64 isa full implementations of 64 not just a poor incomplete copy?
In Soviet Russia, Computer Reboot You!
Zebo - Tuesday, February 22, 2005 - link
"The original Prescott was a Sunday launch. "Well see what I mean..:)
Hans Maulwurf - Tuesday, February 22, 2005 - link
And remember hyperthreading - it uses only a small area on the die and increases power consumption significantly!Oh, and I would still like to know weather it ws 1T or 2T on the Athlon.
Viditor - Tuesday, February 22, 2005 - link
Reflex - First, you may very well be quite correct!Second, not all parts of the die are equal...for example, the ALU runs at twice the clockspeed of the core. The areas affected by 64bit modes MAY be disproportionally higher than the rest of the CPU (I really don't know, which is why I'm asking for a test...).
Third, the design for 64bit on Intel is quite different that on AMD. AMD designed the chip to be hybrid from the ground up, Intel had to "retrofit" their Netburst architecture to accomodate it...while they both function very similarly, their incorporation into the chip is quite dissimilar (e.g. AMD has no double-pumped ALU)
DerekWilson - Monday, February 21, 2005 - link
Intel often does sunday launches --The original Prescott was a Sunday launch.
And there was at least a couple others that I can't recall at the moment.
I've seen other sites say something to the affect of this being a sneaky launch, and I think don't think that is accurate.
I, for one, would prefer Intel not launch parts on a Sunday. But that's how its been and likely how it will be. :-/
Zebo - Monday, February 21, 2005 - link
What's up with Intel sneaking around in the dark for..Sunday night launches on a holiday weekend told me all I needed to know about this new chip release.In sure they still sell billions over AMD but the message is clear from enthusiasts prosective. If you want performance, quiet and cool you buy AMD A64's.(ageing I might add)
johnsonx - Monday, February 21, 2005 - link
In Soviet Russia, message clears YOU!damn, it's hard to stop....
johnsonx - Monday, February 21, 2005 - link
The message is clear: Soviet Russia has failed.Enough already... let's move on to the next catch phrase (if there must be a next one...).
Reflex - Monday, February 21, 2005 - link
Vidiator - 64bit uses very little die space, even once activated its not going to consume any really noticable amount of power. On an Athlon64 its estimated to be about 10% of the core. Considering how much larger a P4 core is it would account for even less percentage wise. I am not including cache in that measurement either which as you saw accounts for 50% or better.So technically it may draw a watt or two, but its not going to change the results significantly...
Viditor - Monday, February 21, 2005 - link
danidentity - "Power consumption is not going to change depending on whether you're running 64-bit apps or not"Is there a reason you expect this? My own rationale is that Intel (I'm assuming here) probably dials down a few things (ALU logic, BISTs, unneeded repeaters, etc...) unless the CPU is operating in 64bit only mode or compatiblity mode (as opposed to legacy mode).
As an example, AMD64 doesn't use the extra registers unless it's in one of the 64bit modes...
I don't know if there will be a swing in power consumption, but I am curious to see any empirical evidence one way or the other...
Derek - Thanks for the heads up on the test (Powernow usage...)!