Can't make both sticks of my 2x8gb kit work together but work Ok when used alone

[JamesGastovski]

The motherboard is an Asus Z97-E/USB3.1. The memkit is a VENGEANCE® Pro Series — 16GB (2 x 8GB) DDR3 DRAM 2400MHz kit.

 

For convenience sake, we'll call both sticks 82 and 83.

When both sticks are used at the same time I can't get them to pass one single pass of memtest, be it in single or dual channel.

BUT when used independently here are the results I get:

Stick 83 on slot B2 won't even pass one single pass without getting loads of errors.

Stick 83 on slot A2 will pass 13 passes without a single error.

Stick 82 will pass 7 pass both on slot B2 and A2.

 

At first I thought that stick 83 was defective but considering that it can work perfectly when used on slot A2 I don't know what to think anymore.

The motherboard seems fine too since the 2x4gb kit 2400mhz of Kingtson memory I also have pass days of memtest without a single error, not matter the slot used.

 

Can't make any sense of any of this. I can still return it to the store, should I? Any help would be appreciated.

[Corsair Art]

This still makes me think the issue is the motherboard given how the different slot makes the module pass without error.

[JamesGastovski]

Yes, that's what I would think too normally but then how can we explain that the same motherboard + CPU combo can pass days of memtest with another memkit?

[Corsair Art]

Yes, that's what I would think too normally but then how can we explain that the same motherboard + CPU combo can pass days of memtest with another memkit?

 

No clue, may be a threshold that the Corsair kit is passing.