Overclocking on the ASUS P5K3 motherboard proved to be interesting. At first we couldn’t get either the Corsair or Kingston DDR3 memory modules to operate at 1600MHz, which shouldn’t be tough to do. After checking the VDIMM voltages it seems that the ASUS motherboard is running more voltage that what is being set in the BIOS. This explained why weird things starting happening when the voltage was increased to over 2.0V. From that point on we kept the voltage to 1.95V for our overclocking experiments. It should also be noted that we couldn’t reach more than 1600MHz when using the orange memory slots (the ones closest to the processor socket). When we moved the memory over to the black memory sockets they easily overclocked over 1700MHz at loose CL10 timings. Basically the take home message here is to keep the voltage UNDER 2.0V and try out both sets of memory slots to see if overclocking is better on one set versus the other.
At CL7 timings the Super Talent and Corsair XMS3 PC3-10666 memory kits just didn’t like the settings and were unable to even post at 1333MHz with 7-7-7 timings. Once the divider was lowered the modules would run CL7 timings, but they could only manage to reach roughly 1200MHz. The OCZ Platinum and Kingston HyperX are rated to run at 1333MHz and 1375MHz right out of the box, but how high can they go? All the way up to 1504MHz for the Kingston HyperX kit! These modules can be overclocked nearly 10%, which is right where we want to it!
At CL8 timings all of the kits improved and the Corsair XMS3 DHX memory kit passed up the Super Talent kit when run at Cl8 timings. The OCZ and Kingston kits got real close to breaking the 1600MHz mark thanks to the Elpida IC’s, while the Corsair and Super Talent kits were aiming at the 1400MHz bar, but just couldn’t make it with their Qimonda IC’s.
The Kingston HyperX PC3-11000 memory kit has seemed to hit a wall and the OCZ kit performed worse at Cl9 timings than it did at CL8. This goes to show that the Elpida IC’s like CL7 or CL8 timings better than CL9 or CL10, so keep this in mind if you pick a kit up. The Corsair XMS3 DHX kit managed to catch up to the Kingston and OCZ kits at CL9, which was impressive. The HyperX kit didn’t like relaxed timings though and failed to overclock to really high frequencies. It’s clear that the IC’s played the biggest role in overclocking and it’s clear that Elipda does tight timings better and Qimonda does loose timings better.
Just for fun we tried the Corsair XMS3 DHX ES memory kit at CL10 timings and found that Qimonda IC’s really liked CL10. The Corsair XMS3 CM3X1024-1333C9DHX kit of memory was able to overclock all the way up to 1712MHz, which is an impressive frequency granted it’s at loose timings.
All of the kits were fantastic to overclock and were able to show that DDR3 memory does scale nicely at a variety of timings.