L2 Cache: 4MB or 2MB?

The majority of Intel's Core 2 Duo line feature a single shared 4MB L2 cache, but the E6300 and E6400 are only equipped with a 2MB cache. Given that the Core 2 Duo doesn't have an on-die memory controller, it is more dependent on larger caches than AMD's Athlon 64 X2, which raises the question - how big of a difference is there between the 2MB L2 and 4MB L2 parts?

Our Core 2 Extreme X6800 (2.93GHz) part, like all X6800s, is unlocked so we could simulate any other Core 2 Duo clock speed with it. We managed to get our hands on a Core 2 Duo E6300 (1.86GHz/2MB) and we were in business.

The graph below features all of the benchmarks we ran on the processors in this review, showing the percent performance improvement from a Core 2 Duo E6300 (1.86GHz/2MB) to a hypothetical 1.86GHz Core 2 Duo with a 4MB L2 cache. The bar labeled "Average" is simply an average of all of the performance improvements graphed on the chart.

The 4MB L2 cache can increase performance by as much as 10% in some situations. Such a performance improvement is definitely tangible, and as applications grow larger in their working data sets then the advantage of a larger cache will only become more visible. Unfortunately, you do pay a price premium for this added performance and future proofing as the cheapest 4MB L2 part is the E6600 priced at $316.

If you're the type to upgrade often, then the extra cache is not worth it as you're not getting enough of a present day increase in performance to justify the added cost. However, if this processor will be the basis for your system for the next several years, we'd strongly recommend picking a 4MB flavor of Core 2.

The Test Memory Latency: No Integrated Memory Controller Necessary
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  • Calin - Friday, July 14, 2006 - link

    A very good part of what Intel makes (processor wise) goes to mainstream and lower-than-mainstream performance (Celeron-like chips). There might be, in the end (of the year), enough production of Core2 to fill the enthusiast/retail market.
    Indeed, the Netburst are obsolete over night...
  • xFlankerx - Friday, July 14, 2006 - link

    Not just Netburst, even the Athlon 64s are obsolete now.

    With the Pentium 4 vs. Athlon 64 debate, atleast there were moments when going with the Pentium 4 could be justified. However, because of the huge difference in performance and prices of the Core 2 Duo and Athlon 64 processors, I think it would be foolish to go for a new Athlon 64 system right now (unless ofcourse you're on a tight budget).
  • Calin - Friday, July 14, 2006 - link

    Yes, Pentium4 was better in so-called media benchmarks, and there were some uber-optimized application that were flying on Pentium4.
    Right now, there are (as stated in article) three competitors: Core2Duo at high price, performance and low power, Athlon64 X2 at lower price, performance and a bit higher power, and PentiumD at dumping prices, even lower performance and quite a bit higher power. It all depends on how much money you would invest.
    I am thinking at a single core Core2, and integrated video mainboard with ATI or NVidia chipset - or a Sempron AM2 3000+. I wonder how cheap a Core2 Solo would be
  • Squidward - Friday, July 14, 2006 - link

    Agreed, an excellent review, I loved Anand's anologies about the dinner table. I get the feeling he may have been thinking Arby's (tm) when he wrote this review. :)

    My goodness does Intel's new lineup impress. I've been using AMD ever since the K6/2 days and was planning on getting an X2 soon, but this review has made me decide to wait it out just a little bit longer.

    Great article guys, keep up the good work.
  • Viditor - Friday, July 14, 2006 - link

    quote:

    Not just Netburst, even the Athlon 64s are obsolete now

    I'd say that the A64 X2s are still quite competitive, depending on your budget and availability of the C2Ds.
    That said, Intel has done a magnificent job with these chips!
    It looks like Conroe will own the high end market until AMD can release K8L...but judging by the review, AMD will own the low end. I can't see anyone buying a PD once AMD drops the prices, nor can I see anyone buying an AMD if they can afford a medium or higher priced system.
  • jkostans - Friday, July 14, 2006 - link

    With the 1.83GHz conroe at $183 and on par with a X2 4600, I don't see the low end going for AMD either.Ultra low end will be a toss up however.
  • Viditor - Saturday, July 15, 2006 - link

    quote:

    With the 1.83GHz conroe at $183 and on par with a X2 4600, I don't see the low end going for AMD either

    If you look at the situation in total, it will probably make more sense...
    1. The X2 has far more inexpensive but fully functional motherboards to choose from.
    2. Supply will be far more constrained on the Conroe than on the X2

    Combos are king in the low end...for example, if you combine an Asus M2NPV-VM with an AM2 X2 3800 (after the price drop), you get a good dual core system with Raid 5, HDTV, nVidia 6150 graphics, Firewire, dual screen (VGA and DVI), and just about every whistle and bell you could want for (est) ~$250. You'd be hard pressed to find just a Conroe-ready motherboard with that kind of functionality for that kind of money (let alone a combo).
  • duploxxx - Friday, July 14, 2006 - link

    correct the real performance king will be for now the conroe starting from 6600 and above. maybe 6400 this will be clear later. but for the budget platform it will be better to buy an x2 3800 or 4200 seeing the price combo it will have. mobo + proc is way cheaper then any intel combo (100$ and more) thats a lot for a budget system.

  • duploxxx - Friday, July 14, 2006 - link

    oh and one big item which is left out of sighht... the performance gain is less on a conroe then on a k8.. its a difference of 15% in identical apps... that's an interesting point for the future... just my opinion
  • Xenoid - Friday, July 14, 2006 - link

    Yes it was a very, very well done review and I will definitely be purchasing one of these bad boys.

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