Having problems upgrading laptop RAM. Is it possible to mix RAMs with different speeds?

[Akopoko]

I have a Toshiba Satellite L855 laptop with one DDR3 4GB, 800MHz (PC3-12800) RAM that came with the laptop.

I wanted to upgrade this to 8GB by purchasing an additional 4GB stick. The laptop specifications say that it has 2 slots for a maximum of 16GB, so I thought this would be fine.

However, when I put in the additional RAM, the computer still showed as only having 4GB. I then tried to use only the new stick to see if it was a problem with that specifically; in this case, my laptop did not boot up at all.

Is it a case of my RAM just being DOA or is there a step I missed/problem with compatibility?

Specs from CPU-Z: I am running Windows 8.1 64-bit. The original RAM included was a Samsung (Part# M471B5273CH0-YK0). The RAM that I am trying to add is a Kingston (Model: KTL-TP1066/4G).

I'm not sure if the problem is that the two RAM are from different companies; or because the Kingston one is apparently " System Specific Memory for Lenovo); or perhaps because the original RAM is a PC3-12800 and the new one is a PC3-8500?


Thanks in advance for the help

 

[itsVance]

The Kingston memory you used is system specific to lenovo(and has different specs).

http://www.newegg.com/Product/Product.aspx?Item=N82E16820139403

If you want to upgrade, you should pick memory that has the same specifications as what your using.
Get the exact modules if possible.

You can search Google shopping like this:

 

[Akopoko]

The Kingston memory you used is system specific to lenovo(and has different specs).

http://www.newegg.com/Product/Product.aspx?Item=N82E16820139403

If you want to upgrade, you should pick memory that has the same specifications as what your using.
Get the exact modules if possible.

You can search Google shopping like this:

Just to clarify, does system specific mean that it only works on Lenovo machines? And I understand that it is always best to use the same spec'd RAM (which I will do going forward) but does the fact that the two RAMs are different speeds (PC3-12800 vs PC3-8500) make a big difference? My initial understanding was that the only effect it would have was making the system run at the slower speed.

 

[itsVance]

The Kingston memory you used is system specific to lenovo(and has different specs).

http://www.newegg.com/Product/Product.aspx?Item=N82E16820139403

If you want to upgrade, you should pick memory that has the same specifications as what your using.
Get the exact modules if possible.

You can search Google shopping like this:

Just to clarify, does system specific mean that it only works on Lenovo machines? And I understand that it is always best to use the same spec'd RAM (which I will do going forward) but does the fact that the two RAMs are different speeds (PC3-12800 vs PC3-8500) make a big difference? My initial understanding was that the only effect it would have was making the system run at the slower speed.

According to that newegg listing, that ram will only work with those specific models. Even if running at a slower speed was the only effect, wouldn't that defeat the purpose of the memory upgrade? I would have to say your modules are not compatible and that is why your computer does not see them all together.