Wierd issue with DDR3 and dual channel.

A

alkemyst

Limp Gawd
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Feb 20, 2005
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I have a GA-990FXA-UD3 and the manual says Channel 0 is DDR3_2 and DDR3_4 and Channel 1 is DDR3_1 and DDR3_3. I have 4 sticks of DDR3, but they are pairs from two different companies.

If I put my Geil in Slot 1 and 2 and the Kingston in 3 and 4 like the manual says I get a memory POST error (one long beep and three short beeps). Placing the Geil in Slot 1/3 and the Kingston in Slot2/4 work fine as does it vice versa. If I try to use any of the single pairs in slots 1 and 2 or 3 and 4 I get the same memory POST error.

This same thing happened with my new TridentX in a GA-Z68XP-UD4 motherboard (I didn't try using slots 1/3 together or 2/4 which I wish I tried now).

Can someone explain why this is happening? CPUZ shows the memory is in Dual Channel Mode.

Å
 
the channels are staggered. so if you have g-g-k-k youre mixing the channels. there also maybe a power/timing mismatches. you should, if you can, run all matched.
 
alkemyst said:
I have a GA-990FXA-UD3 and the manual says Channel 0 is DDR3_2 and DDR3_4 and Channel 1 is DDR3_1 and DDR3_3. I have 4 sticks of DDR3, but they are pairs from two different companies.

If I put my Geil in Slot 1 and 2 and the Kingston in 3 and 4 like the manual says I get a memory POST error (one long beep and three short beeps). Placing the Geil in Slot 1/3 and the Kingston in Slot2/4 work fine as does it vice versa. If I try to use any of the single pairs in slots 1 and 2 or 3 and 4 I get the same memory POST error.

This same thing happened with my new TridentX in a GA-Z68XP-UD4 motherboard (I didn't try using slots 1/3 together or 2/4 which I wish I tried now).

Can someone explain why this is happening? CPUZ shows the memory is in Dual Channel Mode.

Å
Click to expand...
You explained it in your first paragraph.
Channel 0 is slots 2 and 4, Channel 1 is slots 1 and 3.
Not much to confuse.

The start of your second paragraph is not like the manual says, it is the opposite.
 
I am still confused. If I have two sticks of ram that are matched, what slots?
 
alkemyst said:
I am still confused. If I have two sticks of ram that are matched, what slots?
Click to expand...
A ram pair goes into a channel.
Thats why they make the distinction.


The basic way system ram works is this.
A long time ago there was only a need for one memory slot/bank to get enough performance from the memory.
But as processors and other things that use ram got faster/started to work in parallel to each other, it became necessary to use memory banks in parallel.
So memory slots became paired.
If only one of the pair is used, the memory access is only half speed.

Also, modern motherboards can handle different timings for different memory to some extent. Some are better at it than others.
ie like you have, 2 different memory pairs with different timings.
But it can only do this if they are properly paired up, it cannot detect different memory on the same channel.
This is why it works when you properly allocate the ram in channels.

However, this doesnt mean your ram is properly stable.
It may be just stable enough to get you into the bios setup or Windows.
From there you can test it and tune it until it is stable.
Its very possible this is your situation.
If you suffer crashes while running games or other programs, suspect this.
 
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