Optional: DDR600 With CL2.5-4-4-7 Timings
As a second possible usage scenario, GeIL claims operation at DDR600 clock rates with more leisurely timings of CL2.5-4-4-7. This is represented independently of their modules' ability to handle CL1.5 timings. But again, we had to boost input voltage to 3.0V to make things work, just as we did with CL1.5 timings.
But to boost memory speeds from 200 to 300 MHz, it's also necessary to boost CPU speeds for the Athlon 64 itself as well. We increased the system clock manually from 200 to 300 MHz, but we also narrowed the multiplier from 12 to 8, to achieve a CPU speed of 2400 MHz for our Athlon 64 4000+. Because the memory works on a ratio with the system clock, this also produces a memory rate of 300 MHz. Warning: HyperTransport can't sustain significant overclocking. At a 200 MHz base system clock, Athlon 64 systems use a multiplier of 5, which gives a 1 GHz HyperTransport clock rate. To keep that rate under 1 GHz, we lowered its multiplier to 3 to achieve a 900 MHz HT clock rate.
The benchmark results speak for themselves: the memory bandwidth jumps up by a good Gigabyte/second . Effects on respective applications put to work are also noticeably different.
A 300 MHz system clock rate was required to run the memory modules at the same rate, using a 1:1 ratio setting.