Is this setup dual channel ?

[knowledge2121]

My laptop has two RAM slots and it supports dual channel...However, I have an 8GB stick in one slot and a 16GB in another.....is this still dual channel ?

 

[jakjawagon]

In theory it should be possible to have the 8GB stick and half of the 16GB stick in dual channel, with the remaining half of the 16GB working in single channel. Whether your laptop supports this depends on the motherboard. I'd suggest downloading a program such as Speccy which will be able to tell you if your RAM is in dual channel or not.

 

[knowledge2121]

It should be dual channel...it is an Inspiron 15 Gaming 7567...

 

[Karadjgne]

No. It's not dual channel. To be dual channel there's a few requirements.
1. Size must be the same.
2. Same dram technology ie. 2x256Mbit or 2x512Mbit
3. Same dram buss, ie. x8 or x16
4. Single sided or double sided must be used in pairs on separate channels.

In other words, you'd need 2x sticks of 8Gb, both must have the same number of chips and both must have the chips set the same side or sides.

With most newer ram all identically setup, using the same amount of ic's and laptop ram being normally single sided, mostly this isn't an issue, however, because of 2 different size sticks, you'll not have the same amount or size ic's, which disables dual channel.

 

[knowledge2121]

I used Crucial's adviser tool to find a compatible RAM to pair with my DELL memory stick.I found one and then I compared it to my DELL stick and they had the same speed, latency...both are x8, dual rank....everything is identical except the capacity....

and size doesn't have to be the same...read this article :

https://www.intel.com/content/www/us/en/support/articles/000005657/boards-and-kits.html

 

[Karadjgne]

Dual-channel (interleaved) mode
This mode offers higher memory throughput and is enabled when the memory capacities of both DIMM channels are equal. When using different speed DIMMs, the slowest memory timing is used.

Umm ok, that's a direct quote from your post. Size has to be the same, voltage can be different, timings can be different, speeds can be different. But not size.

Further down the page...

Rules to enable dual-channel mode
To achieve dual-channel mode, the following conditions must be met:

Same memory size. Examples: 1 GB, 2 GB, 4 GB.
Matched DIMM configuration in each channel.
Matched in symmetrical memory slots.

What you might be referring to is what's called Flex Mode. That's when (for example) you have 4Gb,4Gb and 8Gb sticks. You place the 2x4Gb in slots 2/4 for dual channel use and the 8Gb can be in either slot 1 or 3 and will run in single channel mode. Grand total will be 16Gb but only the first 8Gb will be in dual channel and get used first, any additional ram needs will be addressed by the slower single channel 8Gb.
Flex mode does offer the chance that 2x sticks of different sizes will partially work in dual channel, however, the same rules apply, the actual ic's must also match, so you'd need ram where both sticks had the same 256 ic's or 512 ic's, but you'll only find that in desktop ram, sometimes. Most laptop ram only has single sided with 2 or 4 ic's. If it's 4 then for a 16Gb stick you'd have 4x4Gb ic's, so that would work if the 8Gb stick had just 2x4Gb ic's. If the 8Gb is using 4x2Gb ic's (far cheaper setup) then it won't work.