[SOLVED] Why do 2 RAM sticks of same brand, model and speed won't work together? (If bought separately)

aranorde

Prominent
Oct 18, 2017
17
0
510
0
I know just because they are of same brand,model and speed they won't work together well, but why exactly is this happening?

I've recently bought G-Skill Aegis DDR4 8GB and 4 months later bought another one, only difference is the manufactured date on the chip and the DRAM Manufacturer on CPUZ (one was "SK hynix" and other was "Samsung").

Initially hey didn't work together, I had to re-seat them or switch slots, then they were working for 4 months then again didn't work together recently (System would say 16GB RAM but only 8GB usable) so I switched slots and now they are working together (weird).

I feel like I wasted time by buying them separately, even though I knew the issue I wanted to experiment and I guess it is safe to say that it won't work well always.

Why is it safe to buy dual sticks than to go with singe separate sticks of same brand?

Thanks.
 

Karadjgne

Titan
Herald
Easy answer.
Ram IC's are made from sheets of silicon. When the silicon is made, even though strong attempts are made to get uniformity, that never happens and you'll end up with slightly different impurities. One sheet might have a little more copper or nickle in it than another sheet which might have traces of iron. This generally doesn't affect the 5 Primary timings, the Cas numbers you always see on ram. However it'll play a somewhat major role in the 40+ secondary and tertiary timings that you almost never see. Those timings have to get along with any other stick too.

Ram made from the same silicon has the best chance of compatability, same batch.

There's other considerations like how the ram is setup on the pcb. There's single rank and dual rank (not to be confused with dual channel). Single rank is ic's all in 1 row, used at one time. Dual rank is 2 sets of single rank, so on an 8Gb stick it's really 2 sets of 4Gb, seen as a 8Gb total. The memory controller deals with the first 4Gb, then the second instead of dealing with the 8Gb in one shot.

Different models/brands can setup differences, the sk Hynix might be dual rank, the Samsung single rank, further complicating how the memory controller interacts with both when set in dual channel. The lower the ram speed/higher timings, the longer the memory controller has to sort out any differences and deal with them. So less chance of overall incompatability. The higher the speed, tighter the timings, the less time the mc has, the easier it is to get frustrated and give you the proverbial finger and the pc gives you a ram error.
 
Sep 6, 2019
38
3
35
0
I feel like I wasted time by buying them separately, even though I knew the issue I wanted to experiment and I guess it is safe to say that it won't work well always.
I can say I make the same as you. Had 8gb and bought another 8gb when I needed it. Slots 1 and 3 didn't worked so i put them in 2 and 4 and works well.
Why is it safe to buy dual sticks than to go with singe separate sticks of same brand?
Thanks.
If you buy dual stick, you have the "warranty" that ram sticks were tested and work well together.

Sent from my OnePlus 6 using Tapatalk
 
Sep 6, 2019
38
3
35
0
I cannot explain the reasoning but I too have experienced problems mixing 2 exact same kits of 2x4gb. However I have been ok mixing different brands in the past.
If you buy from same brand, everything should be fine. I.guess my DRAM manufacturer is different on the second stick too because even if is from the same brand, the logo is a bit different.

Sent from my OnePlus 6 using Tapatalk
 

Karadjgne

Titan
Herald
Easy answer.
Ram IC's are made from sheets of silicon. When the silicon is made, even though strong attempts are made to get uniformity, that never happens and you'll end up with slightly different impurities. One sheet might have a little more copper or nickle in it than another sheet which might have traces of iron. This generally doesn't affect the 5 Primary timings, the Cas numbers you always see on ram. However it'll play a somewhat major role in the 40+ secondary and tertiary timings that you almost never see. Those timings have to get along with any other stick too.

Ram made from the same silicon has the best chance of compatability, same batch.

There's other considerations like how the ram is setup on the pcb. There's single rank and dual rank (not to be confused with dual channel). Single rank is ic's all in 1 row, used at one time. Dual rank is 2 sets of single rank, so on an 8Gb stick it's really 2 sets of 4Gb, seen as a 8Gb total. The memory controller deals with the first 4Gb, then the second instead of dealing with the 8Gb in one shot.

Different models/brands can setup differences, the sk Hynix might be dual rank, the Samsung single rank, further complicating how the memory controller interacts with both when set in dual channel. The lower the ram speed/higher timings, the longer the memory controller has to sort out any differences and deal with them. So less chance of overall incompatability. The higher the speed, tighter the timings, the less time the mc has, the easier it is to get frustrated and give you the proverbial finger and the pc gives you a ram error.
 
Easy answer.
Ram IC's are made from sheets of silicon. When the silicon is made, even though strong attempts are made to get uniformity, that never happens and you'll end up with slightly different impurities. One sheet might have a little more copper or nickle in it than another sheet which might have traces of iron. This generally doesn't affect the 5 Primary timings, the Cas numbers you always see on ram. However it'll play a somewhat major role in the 40+ secondary and tertiary timings that you almost never see. Those timings have to get along with any other stick too.

Ram made from the same silicon has the best chance of compatability, same batch.

There's other considerations like how the ram is setup on the pcb. There's single rank and dual rank (not to be confused with dual channel). Single rank is ic's all in 1 row, used at one time. Dual rank is 2 sets of single rank, so on an 8Gb stick it's really 2 sets of 4Gb, seen as a 8Gb total. The memory controller deals with the first 4Gb, then the second instead of dealing with the 8Gb in one shot.

Different models/brands can setup differences, the sk Hynix might be dual rank, the Samsung single rank, further complicating how the memory controller interacts with both when set in dual channel. The lower the ram speed/higher timings, the longer the memory controller has to sort out any differences and deal with them. So less chance of overall incompatability. The higher the speed, tighter the timings, the less time the mc has, the easier it is to get frustrated and give you the proverbial finger and the pc gives you a ram error.
Great answer. You should save this reply if you have not already. it needs to be used on an almost daily basis on the forums.
 

Karadjgne

Titan
Herald
I learned all that from a Mod who is sadly no longer with us in this world, Tradesman1, who used the example of carpet. You should always buy carpet in 1 batch because buying in multiple batches almost always means the color of the carpet almost never matches up, even if the exact same color. You won't see it until it's down, and you will definitely see the seam through the middle of your living room. Some ppl don't care, some ppl get lucky and have batches in different rooms where the colors differences aren't noticeable, some get unlucky.
 
Reactions: Mandark

aranorde

Prominent
Oct 18, 2017
17
0
510
0
Easy answer.
Ram IC's are made from sheets of silicon. When the silicon is made, even though strong attempts are made to get uniformity, that never happens and you'll end up with slightly different impurities. One sheet might have a little more copper or nickle in it than another sheet which might have traces of iron. This generally doesn't affect the 5 Primary timings, the Cas numbers you always see on ram. However it'll play a somewhat major role in the 40+ secondary and tertiary timings that you almost never see. Those timings have to get along with any other stick too.

Ram made from the same silicon has the best chance of compatability, same batch.

There's other considerations like how the ram is setup on the pcb. There's single rank and dual rank (not to be confused with dual channel). Single rank is ic's all in 1 row, used at one time. Dual rank is 2 sets of single rank, so on an 8Gb stick it's really 2 sets of 4Gb, seen as a 8Gb total. The memory controller deals with the first 4Gb, then the second instead of dealing with the 8Gb in one shot.

Different models/brands can setup differences, the sk Hynix might be dual rank, the Samsung single rank, further complicating how the memory controller interacts with both when set in dual channel. The lower the ram speed/higher timings, the longer the memory controller has to sort out any differences and deal with them. So less chance of overall incompatability. The higher the speed, tighter the timings, the less time the mc has, the easier it is to get frustrated and give you the proverbial finger and the pc gives you a ram error.
Great explanation, I actually had issues with one of the Stick being Dual Rank and the other being Single and I forgot to mention it, it is great that you have mentioned it. Rest of the things you have mentioned are really helpful as I'm currently researching on it online. Thanks a lot. My doubts are solved!
 

ASK THE COMMUNITY

TRENDING THREADS