If a motherboard says it supports Dual-Chanel memory but has 4 slots, can I use all 4?

kaio37k

Distinguished
Apr 3, 2013
239
0
18,680
If I was to get a mobo that supports dual-channel memory but has 4 memory slots and used all 4, would there be any performance decrease?
(I know that 2 slots in dual-channel with same amount would give an increase.)
 


So, if I understand you correctly only two ram modules will fit in each of the 4 because they are different sizes?
 
on new four slot mb if you look at photos there are words or letters next to them and in the mb guild. you see words like slot 0/1/2/3. slots a0/a1/b0/b1.
with 1155/1150 chipset two slots are one bank. two other slots are another bank. if you 16 gigs of ram with 4 sticks. two sicks or 8g are in bank0 two sticks the other 8 are in bank1. to do duel channel you need two stick of the same size ram in the same bank. most new mb will run with only one stick of ram. want you dont want on a gaming rig is mixing ram speeds or ram sizes. if you want 8g of ram use two stick kit of 1.5v ram. 2x4g).
if you want 16g of ram use 2x8g kit.
also look on the motherboard web page there a list for cpu and tested ram called a qal guild. it help you pick out ram that been tested in a mb your looking at.
 
Actually the mobo QVLs are pretty worthless, all they do is take whatever DRAM they have a vailable and stick it in, if it boots up OK it passes, they don't test at the sticks spec freq, see more here:

http://www.gskill.us/forum/showthread.php?t=10566

To figure what will run on your mobo, need to see what freqs your mobo supports, but then even more important is to find what DRAM freqs your CPU can support ....

To better clarify on dual channel each channel has two slots (possible 16GB total in each channel), duall channel will operate with DRAM as long as there is a like amount in each channel, i.e. 1 8GB in each channel or 2 4GB sticks in each channel, if you have dis-similar amounts in each channel - say 4 GB in 1 channel and 8 GB in the other channel - many mobos supports what Intel refers to as flex mode where it will operate 4gb in each as DUAL channel (total of 8GB and the odd 4 GB in single channel)