Why doesn't the RAM mix despite same latency and timing?

[Kohwali]

2x4GB Old RAM

2x8GB New RAM

I put matching sticks in one slot apart.

 

[Kohwali]

They might well play together, no guarantees of course, if you try and have problems give me a shout

ayo

 

[Dark Lord of Tech]

Even identical modules purchased separately can be incompatible.

 

[geofelt]

Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards can be very sensitive to this.
That is why ram vendors will NOT support ram that is not bought in one kit.

 

[weberdarren97]

To quote myself from another thread:

There are things about RAM that we as the buyer can't control. And it's important to understand that just because two sticks are matching specs, doesn't necessarily mean that the internal functions are the same. If internal functions are different, they may not play well together.

Plenty of manufacturers will revise something about their RAM and make changes to the way it's produced, but keep the same part number and model number. If the way it's produced was changed, then internal functions may be different, causing compatibility issues with older sticks that are the same model and part number. This is the main cause of all this confusion. This is also why I recommend getting a kit of memory that has the capacity you want, because it's guaranteed that all memory in a kit was produced exactly the same as each other.

 

[Kohwali]

Checking UEFI and the numbers don't match: http://imgur.com/a/skBUY

Top is the old 2x4GB kit, bottom is the new 2x8GB kit. What do you guys make of this?

EDIT: fixed which one was top and bottom

 

[weberdarren97]

That would be a big part of the problem.

Please reduce the frustration by buying a kit of the capacity you need. You can sell your current memory if you need funds for a kit.

 

[Kohwali]

Shoot, is there nothing I can tweak to get them working?

 

[Tradesman1]

http://www.tomshardware.com/reviews/ddr-dram-myths,4155.html

Items 2 and 6

Can try starting with 1 set, enable XMP then manually change the DRAM voltage to 1.6, save, exit shutdown. Then try adding the other set, if no joy let us know CPU and mobo

 

[Kohwali]

Can try starting with 1 set, enable XMP then manually change the DRAM voltage to 1.6, save, exit shutdown. Then try adding the other set, if no joy let us know CPU and mobo

Didn't work.

CPU: i5-4670
Mobo: ASRock Z87 Pro3

Full build: http://pcpartpicker.com/list/cYWjdC

 

[Tradesman1]

Might look for DDRVTT or CPUVTT voltage and try raising it + 0.06