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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  • invise - Friday, July 14, 2006 - link

    According to page 3 "The Test", you used an Intel D975xBX motherboard (Intel 975X chipset) for the tests in the article. Yet in the picture of the Tuniq Tower on page 18 "Overclocking", there is clearly an Asus board with a gold/copper chipset heatsink, blue PCI-Express 16x slot, and alternating yellow and black DIMM slots. Which board is this? I suspect a P5WD2 or P5N32-SLI, just from looking at pictures online, but from what I can find neither of those has a gold/copper heatsink on the Northbridge.

    I'm curious because you got the board's FSB stable at 445 MHz, which is critical when working with a CPU with a low, locked multiplier. If any other users recognize the board please ID it.
  • spug1 - Friday, July 14, 2006 - link

    quote:

    According to page 3 "The Test", you used an Intel D975xBX motherboard (Intel 975X chipset) for the tests in the article. Yet in the picture of the Tuniq Tower on page 18 "Overclocking", there is clearly an Asus board with a gold/copper chipset heatsink, blue PCI-Express 16x slot, and alternating yellow and black DIMM slots. Which board is this? I suspect a P5WD2 or P5N32-SLI, just from looking at pictures online, but from what I can find neither of those has a gold/copper heatsink on the Northbridge.


    I noticed that too Invise. Can we have some clarification as to whether you used the intel board, or the asus p5w-dh for the testing of conroe?!

    cheerz, :)
  • JarredWalton - Friday, July 14, 2006 - link

    Overclocking was done with the ASUS board. The benchmarks scores were tested on the Intel board as reported on page 3.
  • Suraj - Friday, October 20, 2006 - link

    What other parts did u change when overclocking? I'm very eager to know what exact parts u used when overclocking the e6600.
  • Kiste - Friday, July 14, 2006 - link

    Great review, as always. I have to admit though that I was hoping for a bit more with regard to i965 based mainboards.
  • Gary Key - Friday, July 14, 2006 - link

    quote:

    Great review, as always. I have to admit though that I was hoping for a bit more with regard to i965 based mainboards.


    We have a few P965 boards in house currently, however all of them are undergoing almost daily bios changes. They should be very solid from a performance viewpoint within 30 days but at this time they are still immature and any performance results shown with them are not final.
  • Wesley Fink - Friday, July 14, 2006 - link

    You will see Conroe motherboard reviews the first of the week, and yes, there are 965 boards in the reviews.
  • DrMrLordX - Friday, July 14, 2006 - link

    Could you guys please do a mini-review of this chip? In particular, could you overclock it using a Tuniq Tower 120 or something and give us some idea of how high it will go? I've been wanting to know more about that proc since AM2 launched, but AMD has been doing a lousy job of getting them into retail channels.
  • redpriest_ - Friday, July 14, 2006 - link

    Very detailed, I loved it. But quick question: Your screenshots with cpuid have the stepping as a B1 stepping 5 Conroe - I bought a retail Conroe X6800, and it was a stepping 6 revB2 - and it "only" clocks to 3.466 ghz stably. 3.733 is unstable and 4 ghz is a no boot into Windows; so my question is - is that the stepping you used or was it just a screenshot from an older comparison?
  • Wesley Fink - Friday, July 14, 2006 - link

    Our review samples are all Stepping 5. We also have an earlier Stepping 4 unlocked E6700 that overclocks very well. We understood stepping 5 was the Retail stepping. We will clarify this with Intel later today.

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