DDR4 Single Channel vs Dual Channel

[gregalex87]

I am buying each parts for my new build for few days..CPU and Motherboard ordered from near city so it will reach soon but other things i already bought.. And My RAM is Kingston HyperX Fury DDR4-2400 16GB / 2Gx64 CL15 Memory. I really dunno abt. single channel vs dual channel until now. Is it bad to have single 16gb than 2x8gb ? Please tell what diff. it give to gaming and other things ?

Full Config :

CPU : Intel Core i7 7700K
Motherboard : Asus ROG STRIX Z270E
CPU Cooler : Cooler Master Hyper 212 LED
GPU : Asus ROG Strix GTX 1070 8GB (Buying next month, So not gonna game until buy)
RAM : Kingston HyperX Fury DDR4-2400 16GB / 2Gx64 CL15
HDD : Seagate 3TB BarraCuda 7200 rpm
PSU : CORSAIR RMx Series RM750X
Case : NZXT Noctis 450


More RAM Details :

Type: DDR4
Capacity: 16GB
Speed: PC4-19200 2400MHz
Size & Bit: 2G x 64
Pins: 288pin
ECC: No
Registered: No
Dual Rank x8
CL 15, 1.2V

In these above details i know abt. 2400MHz and CL 15 but dunno what is Size&bit, Pins, ECC, Dual Rank.. Is it anything else important i need to know abt RAM ?

 

[Karadjgne]

Basically, if you have 1 stick of ram, all its info is moved to the cpu in 1 channel. With larger files, this can mean filling up the available bandwidth quickly, so the cpu ends up prioritizing what's taken. Using 2 sticks (1 in each channel) means you move that same info down both channels instead. Generally this can mean about a 20% performance difference in favor of dual channel. The other big advantage of 2x sticks is if there is bad ram. Chances of bad ram are slim, but happen. With just 1 stick, it's impossible to test, with 2x sticks, 1 can be tested separately and replaced if necessary, while still leaving the pc functional somewhat. With 16Gb in 2x sticks, this leaves almost full functionality for everything but the most hungry data users. With just the 1x stick, that means a dead pc until fixed.
ECC ram is specialized ram for server usage, you don't want to use that in your household pc, pins are the little gold teeth on the ram, you want standard ram for pc, not the smaller ram used in laptops. There's a big visible difference. Ddr4 is ddr4, all the same pin count except for laptop ram which is different. Mostly it's not something to worry about.

 

[photonboy]

DUAL CHANNEL provides 2x the bandwidth.

The actual benefit depends on the CPU used, and the type of application being used but you WILL lose performance in some places with a single stick. In many games it's minimal to nothing. In some applications it can be over 30% though that is rare. Most is 0% to 10%.

In general, do NOT use single channel. For that CPU I recommend a 2666MHz CL15 or CL16 kit.

I'll post this then give a link.

*SETUP would go like this:
a) see motherboard manual, but probably #2, #4 slots
b) make sure CPU cooler has no heigh/clearance issue
c) Fully insert the memory and click in place
d) go into BIOS and set "XMP" then save
e) run MEMTEST86 prior to installing Windows www.memtest86.com (run a full pass which is roughly one hour)

 

[photonboy]

http://pcpartpicker.com/product/J27CmG/corsair-memory-cmk16gx4m2a2666c16

That's my top choice. If you want RED or WHITE to match the motherboard, here's some links:

WHITE: http://pcpartpicker.com/product/WY98TW/corsair-vengeance-lpx-16gb-2-x-8gb-ddr4-2666-memory-cmk16gx4m2a2666c16w

RED: http://pcpartpicker.com/product/Xp8H99/corsair-memory-cmk16gx4m2a2666c16r

*It's worth noting that a lot of reviews differ in opinion, but frankly with the minimal cost difference just do it and then don't worry about it again.

 

[gregalex87]

http://pcpartpicker.com/product/J27CmG/corsair-memory-cmk16gx4m2a2666c16

That's my top choice. If you want RED or WHITE to match the motherboard, here's some links:

WHITE: http://pcpartpicker.com/product/WY98TW/corsair-vengeance-lpx-16gb-2-x-8gb-ddr4-2666-memory-cmk16gx4m2a2666c16w

RED: http://pcpartpicker.com/product/Xp8H99/corsair-memory-cmk16gx4m2a2666c16r

As i told above i already bought RAM before few days and unpacked, so what can i do now is buy another 16gb of same RAM after few weeks.

 

[photonboy]

http://pcpartpicker.com/product/J27CmG/corsair-memory-cmk16gx4m2a2666c16

That's my top choice. If you want RED or WHITE to match the motherboard, here's some links:

WHITE: http://pcpartpicker.com/product/WY98TW/corsair-vengeance-lpx-16gb-2-x-8gb-ddr4-2666-memory-cmk16gx4m2a2666c16w

RED: http://pcpartpicker.com/product/Xp8H99/corsair-memory-cmk16gx4m2a2666c16r

As i told above i already bought RAM before few days and unpacked, so what can i do now is buy another 16gb of same RAM after few weeks.

SORRY.
Stick with the single stick unless you are doing really intensive video editing tasks. Here's the best video for you:
https://www.youtube.com/watch?v=9nSX2taw-Y4

I recommend starting at 7 minutes.

UPDATE: He is using 2400MHz DDR3 (not DDR4) memory, and an i5-3570K. The i7-7700K has about 50% to 60% roughly more processing power.

*In a GAME for example, the CPU talks to the system memory but rarely uses ENOUGH of the total CPU processing to saturate even single-channel 2400MHz DDR4.

Conversely, you need to get near 100% CPU utilization (meaning it's talking to the system memory more) before you start to slightly create a memory bottleneck.

So...
I've seen OTHER tests with your system showing larger benefits, even in some games so I'm really not sure what to say. PROBABLY gains are minimal, but they WILL be larger than what the video shows for editing. Probably minimal to nothing for games, but I do know SOME GAMES DEFINITELY WILL BENEFIT SLIGHTLY.

 

[gregalex87]

http://pcpartpicker.com/product/J27CmG/corsair-memory-cmk16gx4m2a2666c16

That's my top choice. If you want RED or WHITE to match the motherboard, here's some links:

WHITE: http://pcpartpicker.com/product/WY98TW/corsair-vengeance-lpx-16gb-2-x-8gb-ddr4-2666-memory-cmk16gx4m2a2666c16w

RED: http://pcpartpicker.com/product/Xp8H99/corsair-memory-cmk16gx4m2a2666c16r

As i told above i already bought RAM before few days and unpacked, so what can i do now is buy another 16gb of same RAM after few weeks.

SORRY.
Stick with the single stick unless you are doing really intensive video editing tasks. Here's the best video for you:
https://www.youtube.com/watch?v=9nSX2taw-Y4

I recommend starting at 7 minutes.

Now he's NOT using the same memory as you, but likely your results would be similar and if not doing video editing or similar you very likely don't need more bandwidth.

*In a GAME for example, the CPU talks to the system memory but rarely uses ENOUGH of the total CPU processing to saturate even single-channel 2400MHz DDR4.

Conversely, you need to get near 100% CPU utilization (meaning it's talking to the system memory more) before you start to slightly create a memory bottleneck.

Nice Info Video. What abt when playing heavy games like Battlefield 1 or any high end games?

 

[photonboy]

I had to update my post. read that again.

It's hard to say for BF1, but here's a tip... if the GPU is the bottleneck improving system memory will give no benefit. If the CPU is the bottleneck system memory MAY (or may not) benefit.

You can see if the GPU is the bottleneck by running a tool like EVGA Precision X to monitor GPU usage. When it's the main bottleneck it should be:

a) near 95% load, AND
b) GPU frequency should be high (1800MHz+ likely depending on temperature)

Hope that helps.

If I'm FORCED to give an answer, I'd say very minimal, frankly not likely observable benefits to games. As I read MORE articles, and incorporate the VIDEO I linked (which had different CPU and memory) I conclude 0% to 15% for some applications, 0% to 5% for games. 0% for most applications.

 

[CelicaGT]

photonboy has the right of it. This is a topic that's been going back and forth since dual channel memory was released. In gaming there is no clear benefit to dual channel and/or memory overclocking. Video and batch photo editing yes, gaming no.

 

[jwcrellin]

It's not "bad" to have one 16gb module rather than 2x8GB sticks. There may be a slight performance drop from only running single channel. I like the idea of having 2 dims just in case one goes bad(redundancy), you can still limp along until a replacement can be sourced.

 

[Karadjgne]

Back in the day, the memory controller was part of the motherboard, so Cas timings were important, the smaller the number, the faster the info was moved out of the ram to the cpu. Now the MC is integrated in the cpu, so Cas timings are about irrelevant. For the past little while, there's been a 1600 MHz cap on MC,thats the certified speed for Intel cpu's, that's been raised with skylake to 2133. With older DX11 titles, those were built around Haswell standards, so ram speed didn't mean much. DX12 is changing the game and some titles have shown a 15fps difference between 2133 and 3200 on the same pc at same settings etc. Back in the day, bandwidth was much smaller, especially on ddr2 ram, and to some extent ddr3 ram, so many mobo's used tri or even quad channel (mostly ddr2) to bump up available bandwidth to maximize performance. It wasn't uncommon to see 4x2Gb instead of 1x8Gb. With the bandwidth capability of DDR4 this is now reversing, 1x stick is capable of exceeding MC requirements, so it's no real loss mostly in performance except in a few cases which h can show @20% performance gains.

Personally, I'd still stick with dual channel ram. It gives a redundancy stick if needed and might possibly use the extra performance on occasion, for minimal expense.

 

[gregalex87]

Thanks for the replies guys. After few weeks i will buy another 16gb of exact same RAM with same frequency and CL. Hopefully it will be future proof.