I've actually heard people talk about the best system, but one thing that stand out is the talk about the core, well still in the dark about this , can anyone with a nice explanation talk about this and the best. Computer guru up to you.

Marv650:
I've actually heard people talk about the best system, but one thing that stand out is the talk about the core, well still in the dark about this , can anyone with a nice explanation talk about this and the best. Computer guru up to you.

To put simply the higher the better, for enhanced processing power and output.
If you never use high demanding softwares or play high graphics games. i3 would serve you nicely.........

So this sound like a core i3 is definately better than i5, could there be any situation when this will vary.

Marv650:
So this sound like a core i3 is definately better than i5, could there be any situation when this will vary.

Although I'm not a computer guru, no, a core i5 is better, core 15 and core 17 processors are quad core while a core 13 is dual core. Core 15 and core 17 processors also allow turbo boost(ability to work faster than the normal clock speed under high work loads) but btw core 13 processors
would require less power and produce less heat.
NB: there are different versions of core 13 and core 15 processors, some of them are comparable.

zzzzy:
Although I'm not a computer guru, no, a core i5 is better, core 15 and core 17 processors are quad core while a core 13 is dual core. Core 15 and core 17 processors also allow turbo boost(ability to work faster than the normal clock speed under high work loads) but btw core 13 processors
would require less power and produce less heat.
NB: there are different versions of core 13 and core 15 processors, some of them are comparable.

i have a lenovo core i3 6gb ram 1tb, could your reason be why its booting is slow?

Marv650:
i have a lenovo core i3 6gb ram 1tb, could your reason be why its booting is slow?

From startup to fully booting up, how many hours?

Marv650:
i have a lenovo core i3 6gb ram 1tb, could your reason be why its booting is slow?

no, i don't think so. Maybe it's because of many apps/files.

zzzzy:
no, i don't think so. Maybe it's because of many apps/files.

i compared it's booting to my brothers own of 2gb ram, the 2gb takes less than 2min while mine could be up to 4.

As much as i can i make sure any app i don't use in a week, month is deleted, so i don't that could be why, and i still have more than 600gb free space

Adding to what others have said, when buying a laptop any small detail in the processor matters. Processors ending with U consume less power thereby having longer battery. eg: i5-6000u

processor ending with K are desktops processors that can be Overclocked

M processors are mobile processors and so on

Another important stuff to check is the generation unless you want to buy a core i7 that's less powerful than a core i3. But there's no much difference in close generations (like 4th & 5th). You consider generation only when it's far off like 2nd & 6th gen

Marv650:
i compared it's booting to my brothers own of 2gb ram, the 2gb takes less than 2min while mine could be up to 4.

Are you both running same operating system? Also check the cache size of both laptops