Memory slots on my MB have different speeds?

[shmimey]

I have had my computer running for some time with only 2 memory cards. This is my setup.

Gigabyte 990FXA-UD3 with an AMD 8350
Memory is G.Skill F3-17000CL9-4GBSR

I did not have this overclocked. I simply turned on the memory XPS settings and that is all.
I was very happy to see that the memory ran at 2133 MHz at 9-11-10.
I ran my PC like this for some time and no I have decided to get two more memory cards.

After I put in the two additional memory cards I was unable to get the same speed on the memory. Now it will not go higher then 1333. This is disappointing.

I pulled the memory out and moved it around to see if one of the cards was bad. All of the memory cards will clock to 2133 with no problems. I eventually found that it was slot 3 and 4 on the motherboard. Slots 3 and 4 on the MB will not run the cards at anything higher then 1333.

Has anyone seen this before? Is there anything I can do? Do you think this is an RMA problem?

 

[Tradesman1]

Might try manually setting to 1866 9-10-9-28, 1.65 and CPU/NB to 1.3 - haven't seen any AMD CPUs running 2133 with 4 sticks

 

[shmimey]

Might try manually setting to 1866 9-10-9-28, 1.65 and CPU/NB to 1.3 - haven't seen any AMD CPUs running 2133 with 4 sticks

I do realize that 2133 is higher then the MB claims to support. 1866 would be nice.

Even if I use only one card at a time the results are the same. Slot 1 and 2 give 2133 and slot 3 and 4 give 1333 on optimized default with XPS.

 

[Tradesman1]

Give it a try

 

[shmimey]

I think I may try to RMA this mobo. I mean I think it is this motherboard.

I have done a lot more testing.

The following testing was done with only one memory card inserted in the motherboard.
The bios is set to default settings and then I turned on the XPS profile to profile 1.
I inserted each memory card into each slot on the board with the following results.
slot 1 = 2133 9-11-10
slot 2 = 2133 9-11-10
slot 3 = 1600 11-11-11
slot 4 = 1600 11-11-11
This seems very odd to me but memtest did pass on each slot. The user manual sugest that you use slots 1 and 2 if you only have 2 cards inserted. Is this by design? are slots 1 and 2 supposed to be faster?

I filled all 4 slots and set the bios back to default with XPS
1600 = 11-11-11
Memtest failed after 12 min every time I ran it. It does not actually report errors it just locks up.

I have had the memory in slots 1 and 2 running at 2133 9-11-10 for over 6 months now.
On this test the memtest passed after running for 10 hours.

I tried to play around with it but I can not get 4 cards to be stable over 1333. The fact that 2 of the slots are slower with only one card in is the problem. Can anyone confirm that this is the mobo and not something else like maybe the memory controller in the CPU?

 

[Tradesman1]

Keep us updated when you get the new mobo, wish it had been something simple

 

[shmimey]

I was sent an email today from Gigabyte. They did perform a repair to my motherboard. They say that they are done testing it now after the repair and it has been shipped back. It took a while but I did send it to them right before the Christmas - New Year break.

 

[shmimey]

The motherboard is working better after the repair Gigabyte made. Gigabyte gets ***** for there warranty RMA service. I have no idea what they did to fix it. I can not tell and the paperwork does not say. The board is definitely the same board and not a new one.
I have 16 gig of memory in the board right now. G.Skill Aries memory 4x4 cards.
The memory is set to 1600 speed 8-8-8-24-34-2T right now.

 

[Tradesman1]

No telling, they should have told you what they've done