The following table lists the maximum overclocking speeds we reached at a common 2.3 V memory supply voltage. Although it is possible to apply more voltage, we do not recommend doing this for permanent system operations, considering that 1.8 V is the default voltage for DDR2 memory and the stated 2.0 to 2.3 V of the memory vendors are already based on selecting memory chips that support higher clock speeds at higher voltages. Hence, 2.3 V is the maximum we’d be willing to accept. 2.4 V and up will not even give you substantially more clock speed anyway.
|Specified Timings||OC Voltage||Labeled DDR2 Speed||Reached OC DDR2 Speed|
|Corsair Dominator TWIN2X4096-9136C5DF||5-5-5-18||2.3V||1142||1176|
|GeIL EVO ONE GE24GB1066C5DC||5-5-5-15||2.3V||1066||1140|
|Kingston HyperX KHX8500D2K2/4G||5-5-5-18||2.3V||1066||1130|
|Mushkin Ascent XP2-8500||5-5-5-15||2.3V||1066||1115|
|OCZ FLEX XLC PC2-9200 Flex II 4 GB Series||5-5-5-15||2.3V||1150||1180|
|Chaintech Apogee GT AU2G732-12GH001||5-5-5-18||2.3V||1200||1188|
All enthusiast-class memory, with the exception of Chaintech’s Apogee GT series, was able to overclock from the default DDR2-1066 speed to DDR2-1115 (Mushkin) and up to DDR2-1180 (OCZ, Corsair). Crucial’s memory kit didn’t go as far, but it’s not an enthusiast product, and it doesn’t even have a heat spreader.
Clearly, there aren’t any large overclocking margins for users to take advantage of. The table shows the overclocking results of each product relative to its specified speed, and using specified timings at a common 2.3 V voltage. The Walton Chaintech Apogee GT only reached 99%, as it failed to reach its specified DDR2-1200 speed. All others provide between 2% and 7% overclocking margin, which really isn’t a lot.