Overclocking

What are the default speeds?

The default core speed for our vanilla SDR GeForce is 120MHz with the memory clocking in at 166MHz. The default core speed of our DDR GeForce is also 120MHz, but the DDR SGRAM is clocked at a pedestrian 150MHz.

SDRAM

DDR SGRAM

Looking at the ESMT RAM, it's 5ns, but the 166MHz default clock and 180MHz maximum overclocking speeds begs the question, why can't you run the memory at 200MHz? The problem isn't with the memory, but rather the trace lengths. The Infineon DDR SGRAM doesn't have the speed rating on the chip, but with a 150MHz default clock, we can guess that the memory is 6ns because Infineon doesn't make 6.5ns DDR SGRAM and the next lowest speed, 7ns, isn't fast enough to handle the 150MHz default speed.

As we mentioned earlier, we were able to overclock the SDRAM memory up to 180MHz from the default 166MHz. We were able to get the 150MHz Infineon DDR SGRAM up to 170MHz from 150MHz.

How'd you do it?

Due to a slight miscommunication between myself and Kenn, I couldn't perform any proper overclocking tests in time for our original GeForce DDR preview. Fear not, we cleared up the issue and put together this little group of benchmarks for your viewing pleasure. We used NVIDIA's own overclocking utility for our tests.

Regedit

CoolBits 3

To enable the overclocking utility we had to edit the registry. With regedit, under HKEY_LOCAL_MACHINE->SOFTWARE->NVIDIA Corporation->Global->NVTweak, change the CoolBits string value to 3. New sliders for the core clock and memory speed should appear in the "Additional GeForce DDR Properties" menu.

NVIDIA's Utility

Using the NVTweak utility, we were able to get the 120/166MHz SDRAM reference card up to 130/180MHz. The DDR SGRAM card went from 120/150MHz to 130/170MHz(340MHz if you count DDR style). We wanted to try yanking off the heatsink and grinding down the chip, but decided Derek Perez(NVIDIA's PR man) wouldn't have been very pleased if we hacked up his merchandise.