Dual Channel RAM problem

elmasbarbo88 · May 20, 2018

I have one Gskill Ripjaws V 8 GB 2400 MHz in my motherboard. If I buy this RAM's 4GB model , are they working dual channel? Thank you for comments.

BlueChinchillaEatingDorito · May 20, 2018

28 minutes ago, elmasbarbo88 said:

I have one Gskill Ripjaws V 8 GB 2400 MHz in my motherboard. If I buy this RAM's 4GB model , are they working dual channel? Thank you for comments.

No because for dual channel operation, both sticks need to be of the same size as well as timings.

2SPOOKY4ME · May 20, 2018

Just now, BlueChinchillaEatingDorito said:

No because for dual channel operation, both sticks need to be of the same size as well as timings.

No, Dual Channel works even if they're different sizes. Timings and Speeds are adjusted by BIOS accordingly. Just tried it yesterday, can confirm it works.

BlueChinchillaEatingDorito · May 20, 2018

1 minute ago, 2SPOOKY4ME said:

No, Dual Channel works even if they're different sizes. Timings and Speeds are adjusted by BIOS accordingly. Just tried it yesterday, can confirm it works.

Your BIOS essentially just set itself to run at the lower speed in order for it still work. It doesn't mean it is running in proper dual channel operation; rather, it's just running in single channel mode. So it will still POST and work, but you will not be gaining the benefits of dual channel, which makes finding the matching memory brand and series a wasted effort.

Excerpt from Intel page on Single and multichannel memory modes.

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.

Configurations that do not match the above conditions revert to single-channel mode. The following conditions do not need to be met:

Same brand
Same timing specifications
Same speed (MHz)

The slowest DIMM module populated in the system decides memory channel speed.

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

2SPOOKY4ME · May 20, 2018

Just now, BlueChinchillaEatingDorito said:

Your BIOS essentially just set itself to run at the lower speed in order for it still work. It doesn't mean it is running in proper dual channel operation; rather, it's just running in single channel mode. So it will still POST and work, but you will not be gaining the benefits of dual channel, which makes finding the matching memory brand and series a wasted effort.

Excerpt from Intel page on Single and multichannel memory modes.

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.

Configurations that do not match the above conditions revert to single-channel mode. The following conditions do not need to be met:

Same brand

Same timing specifications

Same speed (MHz)

The slowest DIMM module populated in the system decides memory channel speed.

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

That's weird, I did a test yesterday if I needed more ram or not to reduce my microstutters and I did manually set my speed and timings. CPU-Z detected that my dimms were in Dual Channel. Benchmarks (latency most importantly) and performance were significantly better.

Thread is here.

Could be case to case basis since we've come so far in terms tech. Not if there's any technological limitations that I'm not aware of.