[SOLVED] RAM pair consistently fails test one way but passes test when modules flipped!?

pilotsh

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May 1, 2014
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Interested to see others experience with this. DDR3 ram testing a couple of pairs. Let’s call one stick in the pair A, and the other stick B.

Every time I test with Stick A in the left and B in the right slot, the test passes. But if I put stick A in the right slot and B in the left slot, the test fails.

This is memtest86, and the test pass or fail is consistent with the above information. Consistently.

Have others heard or experienced this or know if it is actually a ‘thing’ and if so, what causes it?

Cheers.
 
Last edited:

Karadjgne

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Not the same ram. Regardless of actual brand or model number, the 2x different kits are totally different silicon. So although the sticker might say all the same, Primary timings be the same, the secondary and tertiary timings will be different.

If your mobo only has 2x slots, A will be the primary slot, and the memory controller will try to use those timings first. If it finds both to be acceptable, that's what it'll use. Which doesn't mean stick B is good with or stable at those timings, just that the memory controller thinks they are. So on testing with stick A timings, stick B gets errors.

Swap sticks around, stick B timings are good for stick B, but also good for stick A, so no errors.

Welcome to the world of mixing kits and possible errors.
 

pilotsh

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May 1, 2014
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I have two kits of 2 sticks/pair (2x8GB) of Corsair Vengeance RAM. I just checked, and have somehow cross paired them, assuming the different version numbers (v5.23 and 5.29) on the sticks indicate their partner. I will re-pair them based on version number and update.
(I had one pair in my computer and bought an identical pair to trouble shoot but possibly the second pair was a different version number and now they are cross mixed!)

Still, interesting how the memory passes no worries with sticks one way but fails the other way!

(both kits are CMY16GX3M2A2400C11R)
 

Karadjgne

Titan
Ambassador
Not the same ram. Regardless of actual brand or model number, the 2x different kits are totally different silicon. So although the sticker might say all the same, Primary timings be the same, the secondary and tertiary timings will be different.

If your mobo only has 2x slots, A will be the primary slot, and the memory controller will try to use those timings first. If it finds both to be acceptable, that's what it'll use. Which doesn't mean stick B is good with or stable at those timings, just that the memory controller thinks they are. So on testing with stick A timings, stick B gets errors.

Swap sticks around, stick B timings are good for stick B, but also good for stick A, so no errors.

Welcome to the world of mixing kits and possible errors.
 

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