i7 dual channel vs tri channel

[bfdd]

I've had an i7 920 sitting on my shelf for awhile now, haven't really had the spare cash to spend when I bought it(well I did but other things came up) now I'm looking to finally throw it together. The problem is the price difference between a 6gb 3x2 kit vs a 4gb 2x2 kit is ridiculous. I'm wondering about the performance difference between tri channel and dual channel on the i7 and if I'd even notice a difference in performance if I chose to just go with a fast 4gb dual channel kit vs a medium range 6gb tri channel kit. I've read some things that show synthetics really appreciate the bandwidth, but it's actually kind of hard to find these two things compared. Does anyone have any experience with this? Would I be fine saving 60 bucks going with a 4gb kit?


Ok, this thread has run it's course. If the question still needs answered, a new thread without the stupid sidetrack can be made.

AT Mod
Gillbot

 

[Alienwho]

If money is tight you should probably sell the 920 and hop on the 1156 bandwagon.

 

[bfdd]

If money is tight you should probably sell the 920 and hop on the 1156 bandwagon.

I picked it up for 200, money isn't that tight. I'm just wondering if there's much of a performance difference? I mean a 3gb kit tri channel is basically the same price as a 4gb kit dual channel. 6gb kits don't scale well with price for some reason with 4gb kitswhich doesn't make sense to me. If I'm not going to see any drastic performance difference I'll go with a fast 4gb kit, I can upgrade later. I plan on selling another PC I have built for friends to use and parting out this cheap as hell too. The main thing is I want to keep motherboard and ram to the cheaper so I can go 5850 or 5870 without putting to much of a dent in my wallet.

 

[Sahakiel]

If I recall correctly, current apps won't have a noticeable difference. Intel mentioned dual vs tri channel a while back when explaining why 1156 would have one less memory channel. Seems apps don't notice a difference until the core count scales to 8ish. The dual channel limitation is also why Intel hasn't put a 6 or 8 core 1156 processor on their roadmap.

 

[bfdd]

If I recall correctly, current apps won't have a noticeable difference. Intel mentioned dual vs tri channel a while back when explaining why 1156 would have one less memory channel. Seems apps don't notice a difference until the core count scales to 8ish. The dual channel limitation is also why Intel hasn't put a 6 or 8 core 1156 processor on their roadmap.

So I'd be alright currently with a 4gb kit? I mean I can always upgrade to a tri-channel kit later and pawn that one off if I feel like it. If there's no noticeable difference currently I'll go pick it up this weekend.

 

[Emulex]

in server land each memory channel is like 10-12gb/s so filling two out of three slots would yield 33% in peak memory bandwidth loss.

not sure how desktop chipsets avoid that.

 

[bfdd]

in server land each memory channel is like 10-12gb/s so filling two out of three slots would yield 33% in peak memory bandwidth loss.

not sure how desktop chipsets avoid that.

Serverland isn't desktopland though. Obviously if I was building a server I would try to max out my performance, but if I'm not going to get a noticeable loss of performance between dual and tri for desktop useage and gaming, then I have no need to spend the extra 60-70 on a 6gb kit vs a 4gb kit.

 

[ChaiBabbaChai]

Well, here's a few things to think about, having been in a similar situation myself:

1. CompUSA.com has 3x2GB Kingston HyperX 1600MHz C9 kits for $180 w/ free shipping. I bought the 2000MHz kit for $200 and running it at 1800MHz is way fast! Fast as in: 45.9ns latency and 17,747 MB/s read. I could probably overclock it more but why?

2. You could buy a dual channel kit for less than $180 that you could buy a single matched stick of 2GB and add it in later.

3. Buy 3x1GB kit if you need the extra bandwidth (not recommended)

 

[IntelUser2000]

According to claim by Intel like last year it was like this:

Dual Channel: 4 cores
Tri Channel: 6 cores

Unless you are running servers using Gainstown.

 

[Makaveli]

Just look at it this way will it be cheaper to buy 3 sets of dual channel pairs when going with 12GB or is 2 sets of a tripple channel kit more cost effective?

I know you probably won't be going with 12GB to start but just thinking down the road.

 

[bfdd]

Just look at it this way will it be cheaper to buy 3 sets of dual channel pairs when going with 12GB or is 2 sets of a tripple channel kit more cost effective?

I know you probably won't be going with 12GB to start but just thinking down the road.

Actually I am thinking 12gb and it does look cheaper to pick up 3 kits of 4gb than 2 kits of 6gb. I would save 20-30 or more depending on the kits I went with doing 3 x 4gb kits vs 2 x 6gb kits. Figure there's almost a 20% mark up or more PER STICK on some kits between their 4gb version and 6gb kit versions.

 

[lsv]

Just get tri 6gig kit and suck it up. It's not *that* much more money than a 4gig dual kit.

 

[bfdd]

Just get tri 6gig kit and suck it up. It's not *that* much more money than a 4gig dual kit.

105 for a 4gb kit vs 180 for the 6gb kit version. I think I'm better off buying the 4gb kit version and continuing to add from there.

 

[Makaveli]

First of all can you show us where you are getting your pricing and where are you located?

 

[ChaiBabbaChai]

Do you know how to use a calculator? Just do this simple operation:

Total Price

____________ (divided by) = cost per GB.
GB of memory
​

Usually buying a larger kit saves money because the manufacturer saves on packaging costs and sells more units, so they discount somewhat. Just find a good deal, like the one I posted above. 6GB of Dominator GT is ALWAYS going to cost more per GB than 8GB of inferior memory. I think what I bought myself is probably the best bang for the buck.

Remember that if you want to run tight timings and high MHz 3x2 is better than 6x2. But, with triple channel and a 920 it probably still has plenty of RAM bandwidth.
​

 

[cbn]

Actually I am thinking 12gb and it does look cheaper to pick up 3 kits of 4gb than 2 kits of 6gb. I would save 20-30 or more depending on the kits I went with doing 3 x 4gb kits vs 2 x 6gb kits.

Three 4GB dual channel kits can be used on a X58?

I thought it was mandatory to use triple channel memory.

 

[EarthwormJim]

Three 4GB dual channel kits can be used on a X58?

I thought it was mandatory to use triple channel memory.

There's no difference between dual channel memory, triple channel memory or single channel. It's all DDR3. The only thing that manufacturers do with these kits is "guarantee" that those two or three sticks of ram will work together.

You could buy all of your RAM individually and it'll be fine (you could even buy all different speeds, and just run them all at the slowest sticks speed and be fine). You could even run an x58 board with one stick of ram.

This isn't like RDRam where the controller depended on having matched sticks and having every channel terminated.

So yes, provided there are 6 memory slots on the x58 board, you could go with three 2x2gb memory kits.

 

[bfdd]

There's no difference between dual channel memory, triple channel memory or single channel. It's all DDR3. The only thing that manufacturers do with these kits is "guarantee" that those two or three sticks of ram will work together.

You could buy all of your RAM individually and it'll be fine (you could even buy all different speeds, and just run them all at the slowest sticks speed and be fine). You could even run an x58 board with one stick of ram.

This isn't like RDRam where the controller depended on having matched sticks and having every channel terminated.

So yes, provided there are 6 memory slots on the x58 board, you could go with three 2x2gb memory kits.

Sounds like this is the path I'm going to take. I'll start with one 4gb kit, when I get another 100 to throw down on the PC I'll pick up another, until all 6 slots are filled.

 

[ChaiBabbaChai]

There's no difference between dual channel memory, triple channel memory or single channel. It's all DDR3. The only thing that manufacturers do with these kits is "guarantee" that those two or three sticks of ram will work together.

You could buy all of your RAM individually and it'll be fine (you could even buy all different speeds, and just run them all at the slowest sticks speed and be fine). You could even run an x58 board with one stick of ram.

Sounds like this is the path I'm going to take. I'll start with one 4gb kit, when I get another 100 to throw down on the PC I'll pick up another, until all 6 slots are filled.

That's cool but you want to make sure all the sticks match if you want max performance. Also, 3 slots allows tighter timings than if you had 6 slots being used so while it's not as picky as maybe RDRAM, it does make a difference. But, X58 systems yield so much bandwidth it probably won't be that noticeable. From what I've seen users who care about Low latency are mostly audio recording pros.

 

[bfdd]

That's cool but you want to make sure all the sticks match if you want max performance. Also, 3 slots allows tighter timings than if you had 6 slots being used so while it's not as picky as maybe RDRAM, it does make a difference. But, X58 systems yield so much bandwidth it probably won't be that noticeable. From what I've seen users who care about Low latency are mostly audio recording pros.

I will buy 3 of the same kit if it doesn't work then I guess I'm SOL.

 

[cbn]

There's no difference between dual channel memory, triple channel memory or single channel. It's all DDR3. The only thing that manufacturers do with these kits is "guarantee" that those two or three sticks of ram will work together.

You could buy all of your RAM individually and it'll be fine (you could even buy all different speeds, and just run them all at the slowest sticks speed and be fine). You could even run an x58 board with one stick of ram.

This isn't like RDRam where the controller depended on having matched sticks and having every channel terminated.

So yes, provided there are 6 memory slots on the x58 board, you could go with three 2x2gb memory kits.

So a person could buy three 2x2GB dual channel DDR3 kits and the possibility exists they could still end running triple channel?

 

[EarthwormJim]

So a person could buy three 2x2GB dual channel DDR3 kits and the possibility exists they could still end running triple channel?

Yes.

Stop thinking of it as buying dual channel memory, you're just buying 2 sticks of RAM in one packaging (that are guaranteed to work together).

 

[ChaiBabbaChai]

Yes.

Stop thinking of it as buying dual channel memory, you're just buying 2 sticks of RAM in one packaging (that are guaranteed to work together).

This is DDR3 we are discussing, not RDRAM. I think you said that EWJ.

 

[ChaiBabbaChai]

So a person could buy three 2x2GB dual channel DDR3 kits and the possibility exists they could still end running triple channel?

Of course. Look, 3 kits and there are 3 channels on an X58 board. 3 times 2 equals 6, right?

 

[EarthwormJim]

This is DDR3 we are discussing, not RDRAM. I think you said that EWJ.

Yep, I quoted his message which said DDR3.