We've covered the basics of our DDR3 testing in part one of this group test, and we're using the same hardware again to test two more pairs of memory in 4GB kits - the first is Patriots wicked green 1,800MHz Viper series memory with EPP which uses the same Samsung HCF0 chips we've seen before, and the second is Exilir's value 1,600MHz DIMMs that run at just 1.5V, using its own memory chips.
The greatest criticism of DDR3 is that it's generally still expensive compared to the performance gained, however during our recent in depth analysis on Intel's Core i7, we found that running in dual channel mode with a pair of DIMMs afforded very similar performance to triple channel.
Core i7 does enforce some voltage constraints on performance memory, but it could be worth considering a cheaper, performance dual channel kit that offers plenty of overclocking headroom as an interim solution until more triple-channel kits hit the market. More triple channel kits and time will make the market more competitive and the result will be lower prices.
At a request from our last article, we've also included some DDR2 numbers as a performance comparative for you to gauge whether it's worth the upgrade from the usually cheaper DDR2.
We attempted to keep a consistent CPU speed through testing to try to limit the difference in CPU performance over small memory changes. However due to limitations in performance profiles and what chipsets and systems can do at the very high end, we applied a closest fit where necessary.
PC3-1,600MHz (lowest latency, 6-7-6-15-1T, 2.0V, 400MHz x 7.5 - 3.0GHz)
PC3-1,701MHz (rated latency, 8-8-8-24-2T, 2.0V, 425MHz x 7.5 - 3.19GHz)
PC3-1,728MHz (highest overclock, 9-9-9-24-2T, 2.1V, 432MHz x 7 - 3.02GHz)
PC3-1,600MHz (lowest latency, 9-8-8-24-1T, 1.8V, 400MHz x 7.5 - 3.0GHz)
PC3-1,600MHz (rated latency, 9-9-9-27-2T, 1.5V, 400MHz x 7.5 - 3.0GHz)
PC3-1,720MHz (highest overclock, 9-9-9-24-2T, 1.8V, 430MHz x 7 - 3.01GHz)
A few things to note with regards to the motherboards - the nForce 790i Ultra SLI chipset is built for MHz and not for low latency, whereas the Intel X48 is much the opposite. So while the lowest latency the EVGA motherboard will tolerate is CAS-7, the Intel X48 will be happy with CAS-6, providing the DIMMs can do this. On the other hand, we were unable to get the Intel X48 at 1,800MHz DDR3 speeds, stable, whereas the nForce 790i Ultra SLI will happily exceed 2,000MHz in the right circumstances.