DDR2 Roundup: Reaching for 667 and Beyond

New Test Components

Processor

While we report the CPU used for memory testing as the 2.8E LGA 775, the processor is a 3.6ES LGA 775 set to a lower 14 ratio. This particular LGA 775 CPU has demonstrated the ability to run 4.0GHz at near default voltage. This allows a range of available FSB at the lowest 14 multiplier to about 285 or DDR2 760. The production 2.8E LGA 775 has the same 14 multiplier and overclocking results should be comparable on motherboards that have developed methods to bypass the 925X/915 10% overclock lock.

Motherboard

In the first report of manufacturers finding ways to circumvent the Intel 10% overclock lock, we found that the Asus P5AD2 was able to reach a top overclock of 248. This is currently slightly below the memory timing of 250 required to run memory at DDR2 667, at the standard 3:4 Intel memory ratio for DDR2. Further testing for an upcoming 925X motherboard roundup revealed that the Abit AA8 was capable of reaching 258 FSB setting with a stock PCIe video card and SATA hard drive. The Abit is capable of reaching even higher overclocks with an IDE hard drive and/or PCI video because we have found the current limitation to be a result of a non-locking PCIe/SATA bus speed. Abit is working to resolve this issue, if it is resolvable with the 925X chipset, and an updated BIOS with a fixed PCIe/SATA clock should be capable of even higher overclocks. Because the Abit could reach DDR2 667, it was used as the motherboard for memory testing.

Power Supply

The Power Supply for our new test bed is the remarkable OCZ PowerStream 520, which you will see in a future article by Kris Kubicki, the AnandTech power supply guru. While on the expensive side, the OCZ PowerStream 520 has individually powered rails, like the Antec TruePower units. The rails are individually adjustable with LED readouts for special tweaking needs. PowerStream features high wattage, beefed up connectors for video and hard drive, SATA connectors, and both the 24-pin ATX connector required for 925X/915/server and a 20-pin adapter for a standard 875/865/Athlon system. This may be overkill for an average end user, but these are excellent features for a memory test bed where overclocking, power-hungry processors, and power-hungry video is the norm.

Heat Sink Fan

The Thermaltake Jungle512 (CL-P0037) is one of the first third-party LGA 775 heat sinks to appear in our lab. It appears to do a decent job of cooling with the demands of the LGA 775 at overclocked speeds.