Cheap Thrills: Core 2 Duo E6400 Overclocked to 3.33 GHz

A 56% Overclock Puts E6400 On Top!

Everyone expects a multi-thousand dollar PC to perform well, but most of us have bills to pay. Intel's gift to the frugal is a Core 2 Duo processor with half the cache for around two-thirds the cash. To drive home the point that Allendale-core (E6300 and E6400) Core 2 Duos are for cheapskates, Intel also cuts the frequency for a double performance hit almost worthy of the former Celeron name, if not for the high-bandwidth 1066 (266 MHz) Front Side Bus.

Low-cost processors have always lent themselves well to overclocking in the past. This is because all processors in a given family are created equal. Each wafer holds a few hundred processor dies, which, after going through functional tests, are turned into actual products. Whether a die becomes a Core 2 Duo E6500 or E6700 processor mostly depends on customer demand today. Since entry-level processors originate from the same source as that of high-end devices, they usually have the same overclocking potential as well.For entry-level Core 2 Duo devices with only 2 MB instead of 4 MB L2 cache, we might not be able to replace the missing cache, but we can certainly increase the clock rate. Can a simple speed increase overcome the cache deficit? What performance can you expect from an overclocked Core 2 Duo?

Bottom Dollar, Top Performance

Enthusiasts have long viewed overclocking as one path to "cheap performance", but spending $900 on phase-change cooling to get a $200 processor to perform like an $800 processor results in a decrease in value to the tune of $300. With that in mind, spending huge sums of money to get an astronomical overclock out of a cheap part can only be seen as a sport, with the winner buying bragging rights. A list of up-to-date Web prices proves useful:

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Intel Core 2 Duo Desktop Processor Web Prices
ModelLowest PriceUpgrade Cost

Buying a $40 cooler to push the Core 2 Duo E6300 far beyond E6400 performance sounds good at first, until one considers that the E6400 can be moderately overclocked for no additional expense using the cooler it came with. Any cooling upgrade meant to increase overclock ability only becomes a "justified expense" when it takes the lower model processor beyond what the "next model up" can accomplish using its included cooler. In other words, if the E6400 can clock to 3 GHz using the stock cooler, adding a $40 cooler to the E6300 must allow it to clock beyond 3 GHz in order to maintain value.

The same concept works its way up the line for our Core 2 Duo E6400: Spending $95 on a high-end cooler must allow it to beat the E6600 at its stock-cooled overclock limit, or else "bang for the buck" favors the more expensive processor and all our overclocking attempts are in vain. With that in mind, we chose three cooling configurations to test the potential clock speed of a Core 2 Duo E6400: The stock cooler, a giant $70 air cooler by Zalman and a "high value" $160 water cooler from Gigabyte.

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Thomas Soderstrom is a Senior Staff Editor at Tom's Hardware US. He tests and reviews cases, cooling, memory and motherboards.