The Dark Knight: Intel's Core i7by Anand Lal Shimpi & Gary Key on November 3, 2008 12:00 AM EST
- Posted in
What about the Impact of DDR3 Speeds?
Intel only officially supports up to DDR3-1066 on Nehalem, but hitting 1333MHz and 1600MHz isn't a problem thanks to DDR3 being a mature technology that's been in use for a couple of years now.
|Triple Channel DDR3-1066 (9-9-9-20)||Triple Channel DDR3-1333 (9-9-9-20)||Triple Channel DDR3-1600 (9-9-9-24)|
|Memory Tests - Everest v1547|
|Read Bandwidth||13423 MB/s||14127 MB/s||17374 MB/s|
|Write Bandwidth||12401 MB/s||12404 MB/s||14169 MB/s|
|Copy Bandwidth||18074 MB/s||16953 MB/s||19447 MB/s|
|Latency||44.2 ns||38.8 ns||33.5 ns|
|x264 HD Encoding Test (First Pass / Second Pass)||85.3 fps / 30.3 fps||86.4 fps / 30.6 fps||88.1 fps / 30.7 fps|
|WinRAR 3.80 - 602MB Folder||117 seconds||111 seconds||106 seconds|
|Vantage - Memories||6712||6809||6886|
|Vantage - TV and Movies||5637||5716||5716|
|Vantage - Gaming||9849||10570||11013|
|Vantage - Music||4593||4798||4896|
|Vantage - Communications||6422||6486||6630|
|Vantage - Productivity||7676||7803||7819|
|WinRAR (Built in Benchmark)||3306||3520||3707|
|Nero Recode - Office Space - 7.55GB||130 seconds||127 seconds||126 seconds|
|SuperPI - 32M (mins:seconds)||11:52||11:36||11:25|
|Far Cry 2 - Ranch Medium (1680 x 1050)||62.4 fps||62.5 fps||62.7 fps|
|Age of Conan - 1680 x 1050||51.1 fps||51.1 fps||51.1 fps|
|Company of Heroes - 1680 x 1050||133.6 fps||135.8 fps||136.8 fps|
The real world performance benefit from going to DDR3-1066 to 1600, despite having to lower memory timings slightly, is around 3%. The raw increase in memory bandwidth amounts to about 30% and in a completely memory bandwidth bound test like the WinRAR benchmark you're looking at a 12% boost in performance, but that's going to be very rare in most real world scenarios. The reduction in latency is particularly impressive when you jump up to DDR3-1600, it only takes 33.5ns to access main memory.
If you do want the absolute best performance out of your Nehalem system you're going to want a three-channel DDR3-1600+ kit, but you'll only be giving up a couple of percent if you opt for the entry level 1066MHz modules at like timings. Although not shown, in this article anyway, reducing the memory timings to 7-7-7-20 at DDR3-1066 will close the slight performance gap quickly in most instances.