Final Words

The numbers don't lie: Prescott is very well suited for Celeron. Not only do the new Celeron 3xx line of processors perform better than the previous Northwood based Celerons, but even when hampered by a 400MHz FSB, the Prescott Celerons consistently showed improved performance over their predecessors. Even more impressive is the fact that the Celeron 3xx line is able to keep pace with AMD's 2600+ and under Athlon XP line.

The improvements in Prescott's core weren't enough to help it keep up with Northwood as a Pentium 4, even with a double-sized L2 cache. With a 128kb cache, much of Northwood's strong points were ripped away, causing plenty of costly pipeline stalls as we mentioned in last year's budget CPU roundup. With the Prescott based Celeron, Intel's architectural enhancements aimed at avoiding pipeline stalls really had a chance to shine. This is due in no small part to the increased returns on performance when smaller caches are doubled in size.

It's clear that at this L2 cache size, Prescott is able to avoid enough potential pipeline stalls that the increased impact of refilling a 31-stage pipeline is much less significant than Northwood's constant struggle to keep itself busy. It's hard to tell how much of this is due to the improved branch prediction and scheduling as opposed to the fact that the extra 8kb of L1 cache that the Prescott has is a more significant percentage of the overall cache size on Celerons than Pentiums, but either way, the performance advantage over Northwood is there.

The bottom line is that Intel's newest architecture scales down with cache size and bus speed in a much more graceful manner than Northwood.

The only issue left for Intel to deal with is pricing. With both the Athlon XP 2500+ and 2600+ easily available at under $80.00 (as per our RealTime Pricing Engine), Intel really shouldn't be charging much more for their essentially comparable Celeron D parts. The information we were able to track down tells us that the 325 will be priced at $79, the 330 at $89, and the 335 at $117. It's a welcome change to see Intel close the gap between price and performance, as it was distasteful for us to look around and see people being pulled in by ads pushing something like "only $200 more to upgrade form an Athlon XP 2500+ to a 2.7GHz Celeron!" Stuff like that almost makes my stomach cringe. Now that Intel's gotten a handle on performance, we're happy that they are tightening up their belts and starting to rely on quality (rather than the Intel name) to sell products in the value space.

A very special thanks to MonarchComputer.com for sponsoring this review.


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  • Minot - Thursday, June 24, 2004 - link

    Can we get a comparison of a P4 2.4A (Prescott, 1MB L2 cache, 533 MHz FSB) compared to these new Celeron D processors?
  • Pumpkinierre - Thursday, June 24, 2004 - link

    Yeah, there's something more to this than meets the eye. I dont really follow your cache arguments, Derek (and I'm known not to like caches when they are irrelevant). To me what applied to the P4E applies to the celeron D. Its a pity you didnt throw in a 533MHz 2.8E in your benchmarks. I predicted the Prescott celeron would be a good buy but more on the basis of less heat and better o'clocking. The only conclusion I can come of all this, is the Prescott core is better than we think but the cache structure is the problem. Else they've changed something in the pipeline architecture of these celeron Ds which may have ramifications for later stepping P4Es.

  • TrogdorJW - Thursday, June 24, 2004 - link

    #39 - Oh. Dang. Oops. Still, I think I probably would have chuckled more than anything. Who here hasn't made a major mistake at some point in their life? The only problem is that with Internet "publishing", your mistake can be put on the web in minutes rather than days.

    Wonder how many "Flame AnandTech" threads have started up on other hardware forums about the original article?
  • TrogdorJW - Thursday, June 24, 2004 - link

    Just out of curiosity, what's the actual transistor count and die size of the Celeron D?

    With the trimmed down L2 cache, that cuts out about 40 million transistors. If they removed dormant 64-bit stuff from the Prescott core as well (or some other unnecessary additions), we're down to almost the same transistor count as Northwood, except with a 90 nm process.

    Even with 75 million transistors, if it still uses 8 layers like Prescott (and not 6 like Northwood), that would put the die size at less than 70 mm2 by my calculations. Yowza!

    Picture this: 70 mm2 die size CPUs on 300 mm wafers. That gives an absolute maximum of 1009 CPUs per wafer, minus those that are on the outer edge (i.e. partial cores). Even with conservative yields of 60%, we're talking about roughly 600 CPUs per wafer. No wonder they're so cheap.
  • DerekWilson - Thursday, June 24, 2004 - link

    Unfortunately, TrogdorJW, most of the premise of the original publishing was based around the assumption that the Celeron D was able to out perform its predecessor inspite of having an equal sized cache.

    It was a very large error, and certainly worthy of the outrage people have voiced.

    Thanks for sticking up for us though. And please be assured that we will be much more careful. Again, we appologize for the error.
  • TrogdorJW - Thursday, June 24, 2004 - link

    I think some overclocking results are definitely in order, though. Take the Celeron D 325 2.53 GHz part and overclock that to a 166 MHz bus and you get a 3.2 GHz (3.167 GHz) part. It would be interesting to see how that compares to the P4 3.2C and 3.2E - Sure, it will still be (a bit?) slower, but at less than half the cost!

    I'm guessing that a 200 MHz bus is unreachable, as that would give you 3.8 GHz. Then again, from the 915/925 roundup, it seems that 3.8 or 3.9 GHz was reached with many of the Prescott CPUs. Damn... $80 for a CPU that might actually get close to 3.8 GHz!? Either I'm dreaming - entirely possible - or we have a return of the good old 300A overclocking days! Pray for the latter!

    So, seriously, let's have the overclocking results, and compare that to regular P4, Athlon XP, and Athlon 64 results.
  • TrogdorJW - Thursday, June 24, 2004 - link

    Mino, considering that you can't even write a single sentence without spelling and/or grammar errors, I would think that calling the article "full of errors" is rather like the pot calling the kettle black. "I didn't intend to make me looka 'smart', nor is my opinion I am." Way to make yourself look even dumber! Granted, I'm looking at the corrected version of the article, but even if I had read it with the incorrect L2 cache size, it's not that big of a deal. (Unless the original article had statements along the lines of, "even with the same size cache the new Celeron D outperforms... blah blah blah..."?)
  • mino - Thursday, June 24, 2004 - link

    #32 actually U are WRONG, fastest BUDGET proc from AMD is AthlonXP 2800+ which compared to Celeron2.8(here in SK called "Zelenina"-> means "vegetable") is like horse to ponny;)

    However Cel. D is welcome improvement from Cel. based on Willys and Northwds. It is however move from near unusability(but like heater they were gut:) to low usability. Improved computing and heating performance is a good sign, especially ina winret nights when tey turn off heating ussually in my work :).
  • Xaazier - Thursday, June 24, 2004 - link

    intel must be making these things cheap, 90nm process and only 256kb l2

    also the number of celerons sold in cheap emachines and dells is high right?
  • mino - Thursday, June 24, 2004 - link

    #31 Eh, sorry, by "Anand" i meant shortened word "AnandTech".

    My mistake, won't repeat:-).

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