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Discussion Starter · #1 ·
I've been surprised to say the least to see so many posts about i7 (1366) running tri channel vs dual channel.

So just to help clear up this issue, here are some articles discussing the integrated memory controller, latency and ram speed, and of course, dual channel vs tri channel:



And what about memory speed and latency? Well, in real world applications there is little advantage:
Tech Report: Exploring the impact of memory speed on Core i7 performance, A look at channels, bus speeds, and latencies
by Geoff Gasior, December 1, 2008

Quote:
Although three channels of DDR3 memory might seem excessive, the Core i7 really does seem to make good use of faster memory, at least in synthetic tests. But that was to be expected. The real question is whether those gains translate to real-world applications, and it's here that the results are more mixed. Certainly, in scientific computing tests like Euler3d and MyriMatch, which we already know to be sensitive to memory subsystem performance, faster memory can provide tangible performance perks. However, common desktop applications like those highlighted by WorldBench don't benefit much from higher memory clocks or tighter timings. Neither do most games, which at best show minor frame rate improvements that aren't significant enough for most folks to even notice, let alone appreciate.

Digital Daily: CPU Intel Core i7-920 (Bloomfield)
Aleksandr Mitrofanov, Dec 02, 2008

Quote:
This controller is optimized for operation with DDR3 memory and supports 1-, 2-, and 3-channel access modes. In particular, in using the 3-channel access the bandwidth of DDR3-1066 is 25.6 GB/s, which meets the bandwidth of the QPI bus. Therefore, for the Socket LGA 1366 platform the faster memory is not yet needed for now.
Yes the 1366 CPU does support dual and tri channel via the QuickPath Interface (QPI) link and the on-board memory controller. And yes, you can run dual channel instead of tri channel with minimal impact.

And how does dual channel perform against tri channel? Here is a quick read:
Inside HW: Intel Core i7: Dual-Channel vs. Triple-Channel Memory Mode
Djordje Kovacevic, 20 March 2009

Quote:
First test that we run was Everest and we were really shocked with results. It was clear that memory access was faster in case of dual channel memory mode while bandwidth had very close values. After Everest we were slightly less shocked with results that provided WinRAR test that is very sensitive to memory subsystem performances. It showed only 2-3% difference in performances in favor of dual channel mode. Better performance of dual channel mode showed also DivX test where our test showed 3% performance difference in favor of dual channel mode also. Then we started Blender that showed minor differences between system operating in dual and triple channel memory mode. Nuclear MC also showed minor differences between two memory modes tested here, while 3DMark06 showed almost identical results. We all know that Crysis can react positively in case of better memory performances so results weren't that much of a surprise. World in Conflict also showed differences in performance levels of both memory modes. Both gaming tests favored system that operated in triple channel mode.






I hope this clears up all the misconception on OCN.
 

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Crysis @ 3FPS.
What were they thinking?

Good info anyway, this should help lots of people who want to go for an i7 system but can't afford too much RAM.
 

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And how many times I've seen people bashing i7 users for running dual channel instead of tri channel ........ oooh
next time I'll trow this thread in their faces.

Quote:

Originally Posted by DevilGear44 View Post
Kinda makes 1156 a lot more appealing.
sure does! i7 860 FTW
 

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Discussion Starter · #7 ·
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Originally Posted by Cryptedvick View Post
And how many times I've seen people bashing i7 users for running dual channel instead of tri channel ........ oooh
next time I'll trow this thread in their faces.

sure does! i7 860 FTW
Those same posts are what encouraged me to make this thread. I knew it was a 2%-3% performance difference at best, but I didn't expect dual channel to edge out ahead in some of the tests.
 

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Quote:

Originally Posted by ericeod View Post
Those same posts are what encouraged me to make this thread. I knew it was a 2%-3% performance difference at best, but I didn't expect dual channel to edge out ahead in some of the tests.
LOL.I know what you're talking about!

+ REP (virtual) for this thread!!
 
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...So assuming you don't need 12GB of RAM, or 2+ GPUs, what is the point of a 1366-based Core i7 system vs. an 1156 one?
 

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Discussion Starter · #11 ·
Quote:

Originally Posted by DevilGear44 View Post
...So assuming you don't need 12GB of RAM, or 2+ GPUs, what is the point of a 1366-based Core i7 system vs. an 1156 one?
That is about it really. It is the tri channel (not as important) and x16 to multiple video cards that benefit the 1366 socket, and of course the 6-core Gulftown CPUs coming out for the 1366 socket.
 

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Quote:

Originally Posted by ericeod View Post
That is about it really. It is the tri channel (not as important) and x16 to multiple video cards that benefit the 1366 socket, and of course the 6-core Gulftown CPUs coming out for the 1366 socket.
Do you think that DDR3 could perform beter paired with Gulftown?
 

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Discussion Starter · #14 ·
Quote:

Originally Posted by Rocker delMaL View Post
Do you think that DDR3 could perform beter paired with Gulftown?

That I could not tell you. I think we will see a lot of testing on this new core very soon though.
 

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When I first built my i7 system 14 months ago, I immediately noticed that dual-channel was barely slower than tripple, and that a single stick of DDR3-1600 was still faster than dual-channel on my previous P45 + Yorkfield setup.

Quote:

Originally Posted by ericeod View Post
Yes the 1366 CPU does support dual and tri channel via the QuickPath Interface (QPI) link and the on-board memory controller.
A small correction is needed here.

QPI and memory traffic are completely separate.

Quote:

Originally Posted by Rocker delMaL View Post
Do you think that DDR3 could perform beter paired with Gulftown?

The memory/memory controller itself isn't likely to perform any differently, but six cores, when actually used, will obviously be more memory bandwidth dependent than four.
 

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nice thread. i'm glad i found this, as i am contemplating 1156 or 1366. so that sums up the memory factor. how does the pci x lane affect in the real world?
 

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nice + rep

does that mean i could use duel channel eg. 2x2GB corsair XMS3 DDR3 on a X58 based mobo?
 

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Discussion Starter · #20 ·
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Originally Posted by Mr.Pie View Post
nice + rep

does that mean i could use duel channel eg. 2x2GB corsair XMS3 DDR3 on a X58 based mobo?
Yes, most definitely!
 
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