More Info on the Dual Channel RAM sticks.

Badieh

A debate triggered my curiosity earlier today, I would like to discuss it here and try to learn more about the issue. Please be accurate and civil while arguing.

The argument is, is it true that if you have two normal memory DDR3 sticks, you can still achieve a dual channel if you place them in the correct position on the Motherboard, assuming the motherboard supports dual channel? And if this is true, then why do people bother buying the Dual/Triple channel Kits which are usually labeled and priced differently than normal sticks?

yasamoka

The dual channel kits are not labelled and priced differently because they are dual channel...they are so because they are:

1) More stable
2) OC higher
3) come with better voltage regulation and such
4) have heatspreaders
5) Have different clockspeeds for different markets

Getting 2 identical RAM sticks would mostly get you dual channel automatically, without them having to be a kit. But there are always compatibility issues with motherboards that one usually has to make sure of before he buys a motherboard.

As for RAM sticks being installed in incorrect slots, the traces in the PCB leading from the RAM sticks to the memory controller in the CPU work only in the way specified in the manual...meaning you have to place the 2 sticks in the designated slots because ONLY in this way will they run dual channel. The other slots are connected to other pins and into the memory controller differently.

In a nutshell: It is impossible to have dual channel working if you do not follow the correct placements in the RAM slots.

Oh and about pricing:
http://www.amazon.com/Corsair-Vengeance-240-Pin-Platforms-CMZ8GX3M2A1600C9/dp/B004CRSM4I/ref=sr_1_2?ie=UTF8&qid=1345331718&sr=8-2&keywords=corsair+vengeance

8GB DDR3-1600 @ $50 dual channel kit...pricing is really normal...only in Lebanon they are priced so much higher ;)
Kits like this, released recently, have killed the market for budget oriented RAM sticks outside Lebanon. However, here, things are always different...

Badieh

So let's say I have 2 normal identical DD3 1333MHz RAMs, would slotting them in a dual channel position on the Motherboard lead to a higher clock speed automatically? If not, what would I benefit from from doing so?
I know when it comes to RAM kits, I must install them in a dual channel position to benefit from their overclocking (1600MHz, 2000MHz). But, would a normal RAM achieve such a thing?

AvoK95

Like I said before Dual Channel RAM kits are just 2 identical sticks of RAM put in the same box. Yes even normal RAM.
I own the same RAM you have. Using Dual Channels you will benefit from more efficient speed, overclocks and the RAM will basically run just better (Even if they're running the same speed as Single Channel, Dual Channel would make the RAM read/write much faster)

From ASUS P8Z77 manual:
"2 DIMMs: Supports two (2) modules inserted into either the blue slots or the black slots as one pair of Dual-channel memory configuration. We suggest that you install the modules into slots A2 and B2 for better compatibility."
page 32 / 154 (section 2.2.1)

Badieh

Okay, just out of curiosity, and to check with what you are saying, I have switched one of the RAMs into the blue slot, to make them both on the blue one.

These are the results, before and AFTER.... Nothing changed.

AvoK95

It's running in dual channel mode now. That information doesn't change. It just runs better this way.

Badieh

AvoK95 wroteIt's running in dual channel mode now. That information doesn't change. It just runs better this way.

Man I'm sorry, but what exactly is "runs better" to you? If the speed clock remains the same, bandwidth intact, and latency not changed. How exactly would this mean it is running better now?

nuclearcat

http://www.tomshardware.com/reviews/PARALLEL-PROCESSING,1705-11.html

AvoK95

Test Results: Single Vs. Dual Channel RAM
(Note that these are DDR2 , DDR3 has a far bigger result)

yasamoka

Badieh, how are you supposing that bandwidth hasn't changed? Run a memory bandwidth benchmark and see for yourself.

First of all, you calculate RAM bandwidth this way:
DDR means Double Data Rate...meaning 2 transfers per clock cycle. Let's suppose we are trying to calculate the bandwidth offered by a single stick of DDR3-1600 (or DDR3-12800, you'll now know why it can be called this too). 1600MHz = 1.6 billion transfers per second, or 1.6GT/s. This memory is 64-bits wide, meaning 8 bytes per transfer. So bandwidth is 1.6GT/s * 8B/transfer = 12.8GB/s.

Running in dual channel would give you 12.8GB/s * 2 = 25.6GB/s theoretically.

Of course dual channel, triple channel, and quad channel would improve bandwidth.

You don't think X79 Intel chipset supports quad channel RAM just for fun, do you?

Badieh

Avok and nuclearcat, I'm not saying single channel performs better than dual channel, I know quite well that dual channel performs much better than single channel. But to achieve a true dual channel, you need a RAM kit. My question is that I have two normal DDR3 - 1333 RAMs, neither Patriot, HyperX, nor Corsair kits. Would it still achieve a dual channel performance just by slotting it?

Yasamoka, the picture I posted is from the ASUS system information window. It shows all about the RAMs on the Mobo, havent seen anything changed after I re-slotted them to a dual channel position.

yasamoka

It WOULD achieve dual channel, man. Dual channel is independent of RAM sticks. It is a motherboard / CPU / RAM controller feature.

You DO NOT need RAM kits to achieve "true" dual channel.

ASUS system information window does not show you bandwidth. Use a RAM bandwidth benchmark tool for that. I can't remember the tool's name now. When I do, I will link you.

AvoK95

Third time I'm saying ANY Ram can be dual channel as long as both sticks are identical.

Badieh

After reading this article, I got a much better idea on how things work with the dual channel RAM. They suggested I download CPU-Z and check the memory. I did so and this is what I got:

You can clearly see the word "Dual" in the channel, however the DRAM is still 668 MHz, shouldn't it be more in dual channel? And most of the info stated are close to the picture I linked earlier.

yasamoka

Clockspeed does not increase...throughput increases. Let me explain it in another way:

You have a dual core processor with architecture x, running @ 3GHz. You also have a quad core processor of the same architecture x, running @ 3GHz too. The quad core processor has a theoretical maximum of double the processing power, if the workload being processed on the CPU is parallel enough to utilize the additional cores with no extra delays. But the quad core clockspeed does not become 6GHz. You just have more units.

With dual channel, you have 2 units of RAM running at the same speed instead of 1 unit. This gives double the throughput, theoretically speaking.

Badieh

Yeah I understand what you said, just thought the program would actually show the dual performance since it is already showing Dual Channel.

MohammedSF

The reason for making dual/triple/quad channel kits because even you buy identical sticks they aren't 100% identical and have slightly different speed/bandwidth/latency/voltage & OC'ability..

That's because they aren't made from the same identical chips "the same piece of silicon", for that reason manufacturers offers the kits witch is picking 2,3 & 4 sticks from the production line in series witch will guarantee +99% identical sticks..

For example, look at the 2600k processor, some can't OC more than 4.5GHz and some would go 6GHz+ !

Badieh

MohammedSF wroteThe reason for making dual/triple/quad channel kits because even you buy identical sticks they aren't 100% identical and have slightly different speed/bandwidth/latency/voltage & OC'ability..

That's because they aren't made from the same identical chips "the same piece of silicon", for that reason manufacturers offers the kits witch is picking 2,3 & 4 sticks from the production line in series witch will guarantee +99% identical sticks..

For example, look at the 2600k processor, some can't OC more than 4.5GHz and some would go 6GHz+ !

Agreed! Just wish there was some program to actually compute the performance of the Dual channel cause I hardly found any difference when i switched them to dual channel.

yasamoka

Use MaxxMEM and run the benchmark with single channel then dual channel.

Beej

668mhz per cycle, multiply by 2 since its double data rate, you get ~1333 mhz.
And no you dont need kits, you can run different ram sticks if you want from different companies ( as long as voltage is respected).

Example i can run a kingston 800mhz 1.8v ddr2 stick, with hynix 667mhz 1.8v ram. They will run in dual channel, but with 667 speeds.
So you can mix a kingston 1333 mhz ram with samsung 1600 mhz ram and you will be fine. Sometimes you might get problems, but most of the times your A ok.

Generaly kits are sold for a few reasons, these ram sticks have serial number and are bios identified, these sticks are simultanous. Also kits are tested together to insure no such problems would occur. It has nothing to do with oc potential when getting single stick vs kit.
Corsiar dominators gtx6 ram sell by 1 stick.