Would a ram with higher MHz bus than motherboard's overclock better ?

Hi,
You don't post anything about the actual laptop so anyone's guess.

Well I thought the upper listing is all that matters mind you can be logically deduced from bus speeds but anyways lets cut to the chase :
It's a i7 Lenovo laptop DDR3L that comes with 8 GBs of Samsung rams running on bus 1600MHz

Hi,
Look on their website and see what are memory compatibility list for speed for the device.

now this isnt really help , the question is about overclocking , something all manufacturers frown upon , not even one manufacturer would list in specifications he can recommend a ram with higher or lower bus than the one designated for and yet everybody keeps playing with those to squeeze the last drop out of their rigs so directing someone to the formal source isnt the brightest idea .

Hi,
OEM's lock hardware spec's down for that reason
If a different speed is not listed as a OEM upgrade options it's likely not possible

You can use crucial scanner and see what it says is a upgrade option easy enough
Crucial System Scanner | Crucial.com

In general higher speeds are already oc'ed whether that will go higher than that depends on if they work at all

I quite understand that if in theory they will work as people say they will work underclocked to system designated bus i.e the 2133 MHz will tune down to 1600 MHz yet however my question is , is this source of information authentic ? and the second question , would then boosting them to higher speed than 1800 MHz be acceptable since they can actually clock to higher speed than that ? got it ?

Hi,
On a good day a set of memory will down clock to the boards default speed
It's not always the case
I added some trident-z 3200C16 to my x99 rig
It wouldn't even go to bios
3200C14 would and works perfectly so go figure.

If you don't want to go to the laptop's website and simply look at the spec's page (which no oem hardware police) will care lol then take a chance best odds are only 50-50% different spec's memory will post.

Well the official manual says 1600 MHz and that is it .
Crucial says 1866 MHz ram is available option for upgrade .
which brings us to the question , would what work for Crucial work for Kingston ? and if i used rams of 1866 MHz i can boost them to extra couple of 100 MHz than 1800 ?

Hi,
No idea you'd just have to see for yourself :)
What's the price difference crucial has a good compatibility claim/ record
Compare the spec's of each.