When LR first looked at various DDR3 memory modules back in July they were running 1333MHz and had timings that ranged from 7-7-7-20 to 9-9-9-24, which didn't sound too impressive to enthusiasts. We were recently testing some new memory kits from Corsair Memory and was able to reach 4-4-4-12 timings at 1333MHz and even higher! The days of saying DDR3 can't do tight timings is long gone.
"The days of saying DDR3 memory can't run tight timings are long gone now that memory kits can run 1333MHz with 4-4-4-12 timings with a little extra voltage. It just goes to show that it is possible to run tight CL4 or CL5 timings on DDR3 and it is likely that upcoming memory IC's might be able to improve on the frequencies at which these tight timings can be run. The Corsair WIN3X2048-1800C7DFIN G DDR3 memory kit is the only DDR3 kit that I have seen run CL4 memory timings above 1333Mhz..."