[SOLVED] Adding a single RAM stick to a dual channel configuration (DDR3 - 1600 MHz)

Jul 24, 2022
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I am currently running an 11-year-old PC with 2 x 4 GB dual channel DDR3, 1600 MHz RAM. I often find the PC using 95% RAM. So I decided to add one more stick of 8 GB RAM. Would adding the single 8 GB stick cause the 4 GB modules to snap out of dual channel mode. I understand that adding another stick may not work at all but I am unable to source 2 x 8 GB DDR3 RAM sticks in my country.

Thanks
 
Thanks for the input. My motherboad is an LGA 1155, Asus P8Z68 V PRO running an i5-2500k. If I add 2 x 8 gb (matched) sticks in the other channel, would I have 2 x 4 GB dual channel + 2 x 8 GB dual channel? Thanks again.
In a since yes and no it's a hard one to explain on how mixed dual channel works. But here's a shot, in a since you want the smaller set of mixed ram in the first channel seeing as how it's the most used in a since of the word. However what not decoded from there is pushed to the second channel which can hold more then the first as it's the bigger channel. So as channel one decodes one item at a time basically channel two has the room to pick up the slack that one can't
 
Reactions: sandarpanmukherjee
I am currently running an 11-year-old PC with 2 x 4 GB dual channel DDR3, 1600 MHz RAM. I often find the PC using 95% RAM. So I decided to add one more stick of 8 GB RAM. Would adding the single 8 GB stick cause the 4 GB modules to snap out of dual channel mode. I understand that adding another stick may not work at all but I am unable to source 2 x 8 GB DDR3 RAM sticks in my country.

Thanks
The issue most find themselves having with three sticks of separate ram is the frequency they talk at, most of the time the only way to get full potential from a miss match set of ram is to set the timing manually in bios so all match
 
Jul 24, 2022
6
2
15
0
The issue most find themselves having with three sticks of separate ram is the frequency they talk at, most of the time the only way to get full potential from a miss match set of ram is to set the timing manually in bios so all match
So if I were to manually set the latencies of the new RAM stick same as my dual channel RAMs, all should be fine?
 
Reactions: white.a.drew
So if I were to manually set the latencies of the new RAM stick same as my dual channel RAMs, all should be fine?
Yes and no, you want to match the slower sticks speeds, so of the original two sticks at "random numbers not real" 1600 ran at 18-12-13-16, and the new stick is 2000 at 20-15-14-16 you want to match to the original sticks don't match to the higher speeds, another expample of same speed ram different speed clocks, "1600 at 18-12-13-16 but the other stick is 1600 at 20-14-15-16 you want to use speed clock of 18-12-13-16
 
Reactions: CompuGuy71

geofelt

Titan
DDR3 is reasonably tolerant of mixed ram.
Likst the make/model of your motherboard as well as the ram specs that is now installed.
CPU-Z will tell you the motherboard and the memory and spd tabs will identify what you have.
If possible, install the two 4gb sticks on one channel and the new 8gb stick on the other channel.
That way you will run in faster dual channel mode.
If all looks good,
Run memtest86 or memtest86+
They boot from a usb stick and do not use windows.
You can download them here:
If you can run a full pass with NO errors, your ram should be ok.

Running several more passes will sometimes uncover an issue, but it takes more time.
Probably not worth it unless you really suspect a ram issue.
 
Jul 24, 2022
6
2
15
0
DDR3 is reasonably tolerant of mixed ram.
Likst the make/model of your motherboard as well as the ram specs that is now installed.
CPU-Z will tell you the motherboard and the memory and spd tabs will identify what you have.
If possible, install the two 4gb sticks on one channel and the new 8gb stick on the other channel.
That way you will run in faster dual channel mode.
If all looks good,
Run memtest86 or memtest86+
They boot from a usb stick and do not use windows.
You can download them here:
If you can run a full pass with NO errors, your ram should be ok.

Running several more passes will sometimes uncover an issue, but it takes more time.
Probably not worth it unless you really suspect a ram issue.
Thanks for the input. My motherboad is an LGA 1155, Asus P8Z68 V PRO running an i5-2500k. If I add 2 x 8 gb (matched) sticks in the other channel, would I have 2 x 4 GB dual channel + 2 x 8 GB dual channel? Thanks again.
 
Thanks for the input. My motherboad is an LGA 1155, Asus P8Z68 V PRO running an i5-2500k. If I add 2 x 8 gb (matched) sticks in the other channel, would I have 2 x 4 GB dual channel + 2 x 8 GB dual channel? Thanks again.
In a since yes and no it's a hard one to explain on how mixed dual channel works. But here's a shot, in a since you want the smaller set of mixed ram in the first channel seeing as how it's the most used in a since of the word. However what not decoded from there is pushed to the second channel which can hold more then the first as it's the bigger channel. So as channel one decodes one item at a time basically channel two has the room to pick up the slack that one can't
 
Reactions: sandarpanmukherjee
Jul 24, 2022
6
2
15
0
In a since yes and no it's a hard one to explain on how mixed dual channel works. But here's a shot, in a since you want the smaller set of mixed ram in the first channel seeing as how it's the most used in a since of the word. However what not decoded from there is pushed to the second channel which can hold more then the first as it's the bigger channel. So as channel one decodes one item at a time basically channel two has the room to pick up the slack that one can't
So it would make more sense to put 2 x 8gb in the second channel versus a single 8 gb in one of the slots in the second channel?
 
Reactions: white.a.drew
So it would make more sense to put 2 x 8gb in the second channel versus a single 8 gb in one of the slots in the second channel?
If you mix a channel with a 4gb and a 8gb at the same speed but different clock rate then it will fight the sticks on who's speed is right, what should you do what should I do. There the same speed but timings in each sector may very
 
Reactions: sandarpanmukherjee
Jul 24, 2022
6
2
15
0
If you mix a channel with a 4gb and a 8gb at the same speed but different clock rate then it will fight the sticks on who's speed is right, what should you do what should I do. There the same speed but timings in each sector may very
Understood. But I can always manually set the timings in the BIOS right?
 
another expample of same speed ram different speed clocks, "1600 at 18-12-13-16 but the other stick is 1600 at 20-14-15-16 you want to use speed clock of 18-12-13-16
It's exactly opposite.
Lower latency = higher speed.

So ram module 1600 at 20-14-15-16 may not be able to operate at 1600 at 18-12-13-16 speeds and will produce errors.
For increased stability you choose higher latency values.
 
Reactions: sandarpanmukherjee

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