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Why Core 2 Duo E7200?

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6:00 AM - 11/17/2008 by Patrick Schmid and Achim Roos

Our overclocking processor of choice is the Core 2 Duo E7200. It’s based on the 45 nm Wolfdale core, but it runs at a lower bus speed than the E8000-series and it has half the L2 cache capacity: 3 MB instead of 6 MB. While there are still Core 2 Duo E4000 and E6000 processors on the market, the E7000 is effectively the entry-level Core 2 processor. Currently, there are only three E7000 models: the 2.8 GHz E7400, the 2.66 GHz E7300 and the 2.53 GHz E7200.

The same Core 2 Duo E7200 processor was part of our low-power systems comparison, in which we compared G31 motherboard solutions for office and multimedia applications. We found that these boards with the Core 2 Duo E7200 processors are capable of delivering mainstream performance at extremely attractive power requirements of just above 30 W.

E7200 Clocks Like E8500

We chose the E7200 because it runs on the same 9.5x multiplier as the Core 2 Duo E8500. The latter reaches 3.16 GHz on a FSB1333 bus and the 9.5x multiplier, while the Core 2 Duo E7200 reaches 2.53 GHz by multiplying 266 MHz (FSB1066) times 9.5. As a consequence, you can operate the E7200 at E8500 clock speeds simply by switching the bus from FSB1066 to FSB1333. Using the test motherboard’s automatic settings, we didn’t even have to increase the processor voltage manually to achieve 3.16 GHz with the E7200 processor.

Now we still have at least 20 percent additional headroom for overclocking when going from FSB1333 to FSB1600 speed (333 to 400 MHz base clock speed), which is another safe step considering that the same Intel architecture runs on FSB1600 speed at the high end. A further system bus increase to 500 MHz or higher enables more overclocking options for the enthusiast.

Cost Considerations

The Core 2 Duo E8500 lost our vote because of its stepping, which hasn’t reached M0 yet, and because of its substantially higher cost. While we found the Core 2 Duo E7200 on the Web for less than $120, the Core 2 Duo E8500 still costs $210 or more. Yes, the latter will provide better performance thanks to its 6 MB L2 cache, but the 75 percent cost increase by no means justifies the 5 to 10 percent maximum performance increase. See Does Cache Size Really Boost Performance for details. For this article, we analyzed performance with 4 MB, 2 MB and 1 MB L2 cache on systems running exactly the same clock speeds and hardware configurations.

The Core 2 Duo E7200 runs 2.53 GHz at full speed.With SpeedStep enabled, the Core 2 Duo E7200 will reduce its multiplier to x6.0, which results in 1.6 GHz effective clock speed. Voltage dropping to 1.135 V further reduces power consumption.

The Core 2 Duo E8500 runs at parameters similar to those of the E7200, but it’s much more expensive.

Talkback
johnbilicki 11/17/2008 12:29 PM
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Cache is your friend! In example on my moderately modified version of AWStats (web statics programmed in Perl) my socket 754 2.0 GHz 1MB single channel CPU chewed a 120MB access log in 15 seconds flat. My socket 939 2.2GHz 512KB cache CPU took a full minute. Keep in mind the socket 939 processor had a 200Mhz advantage over my socket 754 as well as dual-channel memory support. Both of those benefits had little if any positive effect on the final outcome.

I'd recommend getting the cheapest next increment in cache which would be the E8200. It has 6MB cache instead of 3MB and is $160 which isn't a drastic increase.

Of course more cache doesn't always increase performance. Everything tends to be subjective just like the individual processors.

It would be nice to see an article stressing what types of programs benefit the most from cache. For some people that extra $40 is money well spent while others would see no benefit from spending the extra money.

Slomo4shO 11/17/2008 12:44 PM
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I guess a 40% increase in power consumption isn't too bad for a 50% increase in clock speeds, although at some point it would be more economical to go with the E8400 or E8500(especially if you live overseas where power costs are almost triple of that in the states).

Thanks for the write-up.

jamesl 11/17/2008 1:21 PM
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"Of course more cache doesn't always increase performance. Everything tends to be subjective just like the individual processors."

http://www.xbitlabs.com/articles/c [...] html#sect0

ViDER 11/17/2008 1:21 PM
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Slomo4shO 11/17/2008 1:39 PM
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http://www.anandtech.com/casecooli [...] spx?i=3458

I wish you provided data of a overclocked E8500 to 3.8GHz as well in your power consumption charts.

In current market prices, the E7200 is about $70 cheaper than the E8500. So you pay roughly 60% more initially to step up to a E8500.

If we are to assume that you will get at least 2.5 years of use out of the chip and that there is 25 watt power consumption difference between a E8500 @ 3.8GHz and a E7200 @ 3.8 GHz(on average), then if an individual would keep his PC on 24/7 would actually pay an additional $70 in power charges in the 2.5 year span. At this point it would be better go with the E8500 as the extra cache would provide better performance and there is no difference in the overall price of the system over the average lifespan.

I hope to see full power consumption data in future articles.

Homeboy2 11/17/2008 2:47 PM
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Homeboy2 11/17/2008 2:50 PM
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I only paid 150 for my e8500

johnbilicki 11/17/2008 2:53 PM
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Thanks jamesl, that's a nice comparison across the board. At about 10% performance I'd spend the extra money...not everyone would granted.

Pei-chen 11/17/2008 3:06 PM
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Did the voltage changed when OCed to 3.4GHz. I know you said no put the power consumption doesn't make sense. 15w more for a 283MHz increase in speed and half the cache of E8500?

Pei-chen 11/17/2008 3:13 PM
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Did the voltage changed when overclocked to 3.4GHz? I know you said no but the power consumption increase doesn't make sense at both idle and loaded. 10w more at the same clock and half the cache at idle and 15w more with a 233Mhz clock increase and half the cache. It is as if E7200 are inherently less efficient.

Alien_959 11/17/2008 3:18 PM
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hairycat101 11/17/2008 3:20 PM
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I would have been intersted in seeing both the E7200 and the E8XXX clocked at exactly the same speed to for these tests too. That would have shown how much cache is or isn't important for the individual tests performed. This kind of leaves us guessing...

trinix 11/17/2008 3:29 PM
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@john you are comparing 2 different designs from AMD (who uses another system and has other benefits from cache than intel)and based on that you say everyone should get more cache.

Cache is important, don't get me wrong, but there are some problems with the 8200. The 8200 is harder to overclock to begin with, it's already at 1333 for example.

It really depends on what you need it for and if the money would be wasted or not. The apps described are mostly games and zip. Important for a lot of people, but what difference would it be of use to get a better cpu lesser gpu or the other way around. I think this will help people on budget get a good cpu and gpu.

Cache is still very important for the Core2 design. Now let's see if it's as important for the i7.

trinix 11/17/2008 3:37 PM
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you can compare the results based on fps too. Crysis needs about 300 mhz more to compensate for the loss of cache.

UT3 is very slightly ahead at 300 mhz advantage

World in Conflict needs more then 300 mhz to compensate for the 3mb loss.

If you follow the link a bit higher, you will find a page describing it will be about 5% overall increase in performance, with games up to 10% increase.

So if you have the money, the premium price for cache is worth it. But if you are on a budget, don't worry about the small loss.

clownbaby 11/17/2008 3:39 PM
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so, the title should probably be "How To: Get a 3.8ghz Dual Core for $120". Are the titles written before the articles here?

BSMonitor 11/17/2008 3:42 PM
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Speaking of more E7#00 to come. Newegg already has a 10.5 multiplier version.. E7400 at 2.8GHz for only $145. Bumping FSB just to 1333 already gives you 3.5 GHz!!

Slomo4shO 11/17/2008 3:45 PM
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Pei-chen :
Did the voltage changed when overclocked to 3.4GHz? I know you said no but the power consumption increase doesn't make sense at both idle and loaded. 10w more at the same clock and half the cache at idle and 15w more with a 233Mhz clock increase and half the cache. It is as if E7200 are inherently less efficient.




Quote :
An increase in processor operating frequency not only increases system performance, but also increases the processor power dissipation. The relationship between frequency and power is generalized in the following equation: P = CFV^2 (where P = power, C = capacitance, V = voltage, F = frequency). From this equation, it is evident that power increases linearly with frequency and with the square of voltage.


I hope this answers your question!

vitreoushumor 11/17/2008 4:13 PM
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You're using an $80 ($62 at newegg) heatsink to cool your $120 processor so it performs marginally better than a stock clocked $190 processor. Is that really worth $8, especially if most E8500 retail processors can hit 3.8GHz on the stock cooler?

hairycat101 11/17/2008 4:41 PM
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vitreoushumor :
You're using an $80 ($62 at newegg) heatsink to cool your $120 processor so it performs marginally better than a stock clocked $190 processor. Is that really worth $8, especially if most E8500 retail processors can hit 3.8GHz on the stock cooler?



VERY GOOD POINT. I had a PD805 super overclocked and thought I was cool for while before I did the math and realized I could have had a better CPU/cooler combo for cheaper if I had not had to spend so much extra $$$ on the darn cooler.

x11nt4 11/17/2008 4:49 PM
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E8500 is $188.99 with free shipping at newegg. This has been their price for at least a week. Not $210+. I don't know what websites you people writing these articles look at, but I always check newegg first for all prices. I'll pay the extra $60 for double the cache.


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