No buy the 7700k option. Games depends pretty much on single core performance, so more cores with less clock speed won't help your game that much( except if your are playing Minecraft).
With the exception of indie games, the vast majority of games released by large game publishers can take advantage of at least dual core CPUs, and many popular "AAA" games can use 4 cores. However, I do not know of many games that can take advantage of 6 cores and Hyper Threading. The only exception that I am aware of is Overwatch, then again, I do not play many games anymore.
OP, the i7-7700K is a desktop CPU. Those laptops have the i7-7700HQ CPU, it has lower clockspeed compared to the desktop i7-7700k and cannot be overclocked.
Intel has not made any official statements about a Coffee Lake mobile CPU yet. The current 8th generation mobile CPUs are simply refreshed Kaby Lake CPUs. The "u" model CPUs now have 4 cores rather than only 2 cores.
If you are waiting for a Coffee Lake mobile CPU, you could be waiting a "long time". Or it may not come out at all. Intel is hoping to work out the kinks in their 10mm manufacturing process (current Intel CPUs use the 14nm+ process) in late 2018. It could be possible they might skip mobile Coffee Lake and move on to Cannon Lake.
MERGED QUESTION Question from boss311 : "Wait or buy the current i7"
I want to buy a gaming laptop.
1.msi ge73vr raider
2. Dell alienware 17
Both have i7 7700k gtx 1070 and 16 GB of ram
So should I buy it now or wait for the i7 8700k option to arrive.
Good deal, yes. 8700k laptop may take several months and can be expensive. If you need it urgently, get it after coffee lake release for good discount. If you can wait and have the budget, wait for coffee lake, much better performance in AAA games.
For sure wait for coffeelake, more cores for around same amount of money.
TJ Hooker :
You're talking about laptops, which means they have mobile CPUs (i.e. 7700HQ), not desktop CPUs (i.e. 7700K).
I haven't heard any news on what to expect from the i7-8700HQ (or whatever the next gen, full power mobile i7 is called). Desktop i7's are going from 4 to 6 cores with kaby lake, but there's no guarantee they'll do the same for mobile.