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Overclocking

System Builder Marathon, March 2010: $750 Gaming PC
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Overclocking

Three processing cores and fairly high 2.9 GHz stock core speeds allow the Athlon II X3 435 to put up a good show for such an affordable CPU. But with stock benchmarks out of the way, we certainly wanted to see what sort of extra performance could be squeezed out of our $750 system.

As we have often stated, overclocking is luck of the draw and results vary from chip to chip. Our Athlon II came with a high 1.425V VID, meaning we wouldn’t be pushing more than about 5% (0.075V) more volts when dialing in our overclock.

This isn’t a Black Edition chip, so core speeds are raised by increasing the reference clock from the stock 200 MHz. For additional information on how to do this, refer to our guide on overclocking a locked AMD processor.

Here the fun all begins within Gigabyte’s MB Intelligent Tweaker (M.I.T.) BIOS menu. We lowered the CPU northbridge frequency, HyperTransport link frequency, CPU clock ratio multipliers (as well as the memory clock ratio), and then proceeded to find the maximum reference clock for our motherboard and CPU combo. Testing halted upon reaching a stable 300 MHz, as we knew this was beyond necessary given the high available 14.5x CPU multiplier.

Attention now turns toward finding the maximum core speed for our three-core Athlon II CPU. At stock 1.425V, we find stability at 3.5 GHz (14 x 250 MHz). A 0.075V bump in the CPU voltage control and CPU northbridge VID control (to 1.5V and 1.25V, respectively) gives us a maximum stable overclock of 3,668 MHz. It doesn't matter whether "14 x 262 MHz" or "14.5 x 253 MHz" is used, so we have both options available for memory and northbridge tweaking. While these aren’t outstanding results, they fall right in line with the majority of test samples used in launch reviews.

Despite the 1.5V rating of our G.Skill Ripjaws, the lowest available DDR voltage in Gigabyte’s F3 BIOS was 1.6V. After a boost to 1.65V, we still had no luck with stable RAM frequency above DDR3-1659, so extra performance was instead gained by running DDR3-1396 at reduced 7-8-7-15 timings, as well as jacking the northbridge frequency up to 2,620 MHz.

As mentioned above, these Sapphire Radeon HD 4850s were already slightly overclocked out of the box. But both of these cards have far more to give, and are stable all the way up to Catalyst Control Center's maximum 700 MHz GPU core and 1,200 MHz (2,400 MHz effective) memory. Considering the exact limit was unknown, the memory was knocked down 20 MHz for performance testing.

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