12GB ram only 3.99GB usable

[MoJo86]

i recently installed 2 x 4GB ram chips but my pc doesnt "use" them.
Im running windows 7 64 bit.



any advise on how to make the ram work?

 

[Mystere]

How does 2x4 = 12? Or do you mean you added an additional 2x4 to your existing 2x2?

 

[MoJo86]

yes i had 2 x 2 in and i added the 2 x 4

 

[DocBrown]

Are they the same brand, type, speed, etc ? a screen snip of CPU-z (memory) would help.

Also systen configuration (Advanced Options)

 

[Mystere]

Try swapping the memory modules so that the 4G's are in the current 2G channels and vice versa. Also, try removing the 2 2GB modules and see if you it gives you 8GB.

 

[dsperber]

I suspect the new memory may not have matched the existing memory in terms of timings, etc.

How about downloading and installing CPU-Z, run it and then post four screenshots of the four memory slots using the SPD tab.

Also, post a screenshot of the Memory tab.

These should be very helpful in figuring out what's really going on.

 

[MoJo86]

I have tried to run the chips seperate... but it wont start with either of the 4 gb chips on it own

[/ATTACH]

 

[Mystere]

More than likely your memory is not compatible with your motherboard. You could try tweaking the voltage and other settings, but your motherboard likely has very specific requirements for memory. It looks like you have a P55 chipset which means you have to have memory that is designed for 1.5-1.65 volts. Can you post the specs of your new memory, or at least it's make and model number?

 

[MoJo86]

 

[DocBrown]

Thanks for that last CPU-Z snip.

I think you need the 4gb sticks in slots 1 & 3 & the 2gb sticks in slots 2 & 4

They all look like the same speed but you have 3 diff mfgs of memory.

 

[MoJo86]

thanx ill try that now... the samsung was a shipping error. and the trancesends will be out as soon as i get the 4gb chips up and running

 

[Mystere]

As DocBrown says, you have to install memory of the same type in the same channels. Channels run 1/3 and 2/4, so when you have only two sticks installed you place them in slot 1 and 3, and when you have four, you place the 2GB's in slots 1 and 3, and the 4GB's in slots 2 and 4. Typically, most motherboards color code these slots, meaning you install the pairs in the same color slots.

Also, as DocBrown says, your 4GB's chips are from two different manufacturers. The timings look similar, but that might still cause a problem. First, put your sticks in the right slots.