Running 12GB of DDR3 Triple Channel Memory on Intel Core i7 PlatformsSun, Jan 18, 2009 - 12:00 AM
Manually Setting The Timings At 12GB
Since I am using Windows Vista Ultimate 64-bit all 12GB of system memory was dectectable by the operating system and could be used.
Checking CPU-Z 1.49 to see if everything was running correctly, but with the X.M.P. settings the timings were 9-9-9-24 2T. This is great considering the system is running 12GB of memory in triple channel mode, but you can always try for more.
To check out baseline performance I fired up Sandra and found that the Integer and Float memory bandwidth was right at 28,032MB/Sec. Getting 28.03GB/Sec of throughput with 12GB of memory in the system is insane!
Next I spent an afternoon trying to find what the tightest possible timings were for 12GB of memory at 1600MHz was and discovered that 8-7-7-20 1T timings were not only possible, but Prime 95 stable as well.
I couldn’t believe that running six 2GB memory modules at 1600MHz with 8-7-7-20 1T timings was even possible let alone stable with just 1.6V. This just goes to show how well designed the memory controller is on the Intel Core i7 Processor and that these Corsair memory kits are very solid parts. This kit was able to run at 8-7-6-20 1T performance settings as well, but no performance gain was noted. I tried for hours to reach 7-7-7 timings with stability, but it couldn’t be done on this particular motherboard and memory kits. I even through 1.7V to the memory and still couldn’t get it.
With all 12GB of memory running at 1600MHz with 8-7-7-20 1T timings the Sandra 2009 SP2 memory performance jumped up to 28.93GB/Sec, which is 900MB/Sec higher than what I started with when using 9-9-9-24 1T timings. A 3% performance increase by lowering timings isn’t significant, but hey every single bit helps and it is nearly 1GB/sec more throughput.
Now that you know that 12GB of memory can run tight timings, I can show you how fast they can reach.