Problem with 24 gb of ram on a Gigabyte z77x-ud5h board

[Stoneburner]

I have 2x8 of G.skill 1600 (ares) CL 10
I have 2x4 of G.skill 1600 (ripjaw) CL 9

For some reason, I cannot get both sets to work on my board at the same time. If all 4 dimms are installed, then the board will flash on, do weird crap for 30 seconds, and then restart. The codes on the board display indicate memory issues.

I understand that dual channel memory has to be a matching pair, but I always thought that only the memory on the same channel has to match.

I've also rechecked the Dimm positions. I thought board makers had moved away from alternating slots for the memory channels. For example.

|1| |2| |3| |4|

IF each of those represents a dimm, according to the manual for my board, 1 and 3 have to match and 2 and 4 have to match. This is how dual channel worked on my Asus p4g8x way back in the day, but i thought board makers had changed the paradgm so that 1-2 would be a pair and 3-4 would be a pair.

Thanks for any assistance.

[bankster55]

you cant mismatch sticks with dif timings
you cant mismatch sticks from dif packages
(all must be from 1 pak)
You cant mismatch stick sizes

I would say if you wished to make sure your ram wouldnt run right, you couldnt have done better

[Batmeat]

Bank is right. you can't mismatch sticks from different packs and expect it to work.

[Stoneburner]

Let's say I just wanted to run it all in single channel mode. I used to be able to stick 4 mismatched sticks in 4 separate dimms and it would work fine.

So, if you have 4 dimms and are running dual channel, you have to have 4 matched sticks? I thought only each particular pair had to match... In fact, I've done mismatched sizes and pairs on computers recently. For example, another computer with a i5-750, i stuck 2x2 1600 and 2x4 1600 (all g.skill ripjaws). That works fine and runs in dual channel mode.

[vailr]

Quote from the manual:

Due to CPU limitations, read the following guidelines before installing the memory in Dual Channel mode.
1. Dual Channel mode cannot be enabled if only one DDR3 memory module is installed.
2. When enabling Dual Channel mode with two or four memory modules, it is recommended that memory of the same capacity, brand, speed, and chips be used. For optimum performance, when enabling Dual Channel mode with two memory modules, we recommend that you install them in the DDR3_1 and DDR3_2 sockets.

The included diagram shows the slot numbering as:
Back to front: #1-#3-#2-#4
Back = furthest from I/O panel.
So when installing only 2 modules, they should be installed in the #1 & #2 numbered slots.

So to answer your question:
"i thought board makers had changed the paradgm so that 1-2 would be a pair and 3-4 would be a pair."
No, there's been no change that I see, as far as alternating slots still being the correct memory module placement. Keeps the modules cooler that way.

[greenhawk]

if both sets work, you just need to find a common voltage and timmings and set them manually to get the system stable. Does defeat the purpose of buying fast ram though.

[Stoneburner]

Originally Posted by vailr

Quote from the manual:

Due to CPU limitations, read the following guidelines before installing the memory in Dual Channel mode.
1. Dual Channel mode cannot be enabled if only one DDR3 memory module is installed.
2. When enabling Dual Channel mode with two or four memory modules, it is recommended that memory of the same capacity, brand, speed, and chips be used. For optimum performance, when enabling Dual Channel mode with two memory modules, we recommend that you install them in the DDR3_1 and DDR3_2 sockets.

The included diagram shows the slot numbering as:
Back to front: #1-#3-#2-#4
Back = furthest from I/O panel.
So when installing only 2 modules, they should be installed in the #1 & #2 numbered slots.

So to answer your question:
"i thought board makers had changed the paradgm so that 1-2 would be a pair and 3-4 would be a pair."
No, there's been no change that I see, as far as alternating slots still being the correct memory module placement. Keeps the modules cooler that way.

That's the portion I was focused on. It appears they are recommending 4 matched sticks instead of 2 and 2. That makes no sense since the bios reads and adjusts the two "Channels" independently.

Thanks for the help.

[vailr]

Can you boot to bios with 4 sticks installed as: (back to front) 8-4-8-4 ?

[Gunbuster]

Just in case are you on the latest BIOS?