Quad vs double dual

[Moosedoctor]

Hi,

 

I have an Asus X-299 motherboard.  For the last couple of years I have had 4x4GB running on quad channel on one side of the CPU.  The other four DRAM slots on the other side are empty.  I just got curious what would happen if I were to run 2x4GB on dual channe on both sidesl.  How would it affect performance?

 

THanks

[Hairless Monkey]

You've been running dual channel with 2 dims per channel.

 

You can only run quad channel by using "both sides".

 

You will double your memory bandwidth by doing it properly.

[Hairless Monkey]

Reference page 1-5

 

https://dlcdnets.asus.com/pub/ASUS/mb/LGA2066/PRIME_X299-DELUXE/E13088_PRIME_X299-DELUXE_UM_V2_WEB.pdf

[Moonzy]

21 minutes ago, Moosedoctor said:

last couple of years I have had 4x4GB running on quad channel on one side of the CPU

mmm... dont quad channel require each stick of RAM be one slot apart, even on x299?

-flips an x299 asus board manual-

 

seems to me you're running dual channel, dual rank 

channel C and D, slot 1 and 2, and you filled in each slot with 4gb stick, which are single rank

so dual channel (C D) and dual rank on each channel (two stick in each 1 and 2 for each channel)

 

21 minutes ago, Moosedoctor said:

How would it affect performance?

difference between quad channel single rank vs dual channel dual rank

 

quad channel = higher bandwidth (almost 2x of the other config but not quite)

memory rank = more efficient in memory bandwidth, but small contribution, main advantage is more memory to be added to each channel when each rank is full

 

here's a video

 

recommended config: quad-channel, single rank, the highest bandwidth

[BobVonBob]

You've got it backwards. You've actually been running two dual channel sets this whole time. The different sides of the CPU aren't four different channels, each color of RAM slot is four channels.

 

Performance is improved marginally by the jump from single to dual channel, but unless you're doing memory heavy tasks it isn't improved much more by tri- or quad- channel memory. If you've got the inclination I'd move the two RAM sticks in the color closer to the socket to the same color as the other sticks on the other side of the CPU. Picture for clarity.

 

[Oshino Shinobu]

You've had 4 DIMMs in dual channel if they're all in the slots on one side of the CPU. You need to populate each channel to utilise quad channel. ASUS X299 boards are setup like this:

 

[Moosedoctor]

Thank you all!