The Dark Knight: Intel's Core i7
by Anand Lal Shimpi & Gary Key on November 3, 2008 12:00 AM EST- Posted in
- CPUs
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 |
| PCMark Vantage | 7490 | 7569 | 8102 |
| 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.
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Spectator - Monday, November 3, 2008 - link
that sht is totally logical.And Im proper impressed. I would do that.
you can re-process your entire stock at whim to satisfy the current market. that sht deserves some praise, even more so when die shrinks happen. Its an apparently seemless transition. Unless world works it out and learns how to mod existing chips?
Chukkle. but hey im drunk; and I dont care. I just thought that would be a logical step. Im still waiting for cheap SSD's :P
Spectator.
tential - Monday, November 3, 2008 - link
We already knew nehalem wasn't going to be that much of a game changer. The blog posts you guys had up weeks ago said that because of the cache sizes and stuff not to expect huge gains in performance of games if any. However because of hyperthreading I think there also needs to be some tests to see how multi tasking goes. No doubt those gains will be huge. Virus scanning while playing games and other things should have extremely nice benefits you would think. Those tests would be most interesting although when I buy my PC nehalem will be mainstream.npp - Monday, November 3, 2008 - link
I'm very curious to see some scientific results from the new CPUs, MATLAB and Mathematica benchmarks, and maybe some more. It's interesting to see if Core i7 can deliver something on these fronts, too.pervisanathema - Monday, November 3, 2008 - link
I was afraid Nehalem was going to be a game changer. My wallet is grateful that its overall performance gains do not even come close to justifying dumping my entire platform. My x3350 @ 3.6GHz will be just fine for quite some time yet. :)Additionally, its relatively high price means that AMD can still be competitive in the budget to low mid range market which is good for my wallet as well. Intel needs competition.
iwodo - Monday, November 3, 2008 - link
Since there are virtually no performance lost when using Dual Channel. Hopefully we will see some high performance DDR3 with low Latency next year?And which means apart from having half the core, Desktop version doesn't look so bad.
And since you state the Socket 1366 will be able to sit a Eight Core inside, i expect the 11xx socket will be able to suit a Quad Core as well?
So why we dont just have 13xx Socket to fit it all? Is the cost really that high?
QChronoD - Monday, November 3, 2008 - link
How long are they going to utilize this new socket??$284 for the i7-920 isn't bad, but will it be worth the extra to buy a top end board that will appreciate a CPU upgrade 1-2 years later? Or is this going to be useless once Intel Ticks in '10?
Strid - Monday, November 3, 2008 - link
Great article. I enjoyed reading it. One thing I stumbled upon though."The PS/2 keyboard port is a nod to the overclocking crowd as is the clear CMOS switch."
What makes a PS/2 port good for overclockers? I see the use for the clear CMOS switch, but ...
3DoubleD - Monday, November 3, 2008 - link
In my experience USB keyboards do not consistently allow input during the POST screen. If you are overclocking and want to enter the BIOS or cancel an overclock you need a keyboard that works immediately once the POST screen appears. I've been caught with only a USB keyboard and I got stuck with a bad overclock and had to reset the CMOS to gain control back because I couldn't cancel the overclock.Clauzii - Monday, November 3, 2008 - link
I thought the "USB Legacy support" mode was for exactly that? So legacy mode is for when the PC are booted in DOS, but not during pre?sprockkets - Monday, November 3, 2008 - link
No, USB legacy support is for support during boot up and for the time you need input before an OS takes control of the system. However, as already mentioned, sometimes USB keyboards just don't work in a BIOS at startup for one reason or another, and in my opinion, this means they should NEVER get rid of the old PS/2 port.I ran into this problem with a Shuttle XPC with the G33 chipset, which had no ps/2 ports on it. There was a 50/50 chance it would not work.