Go for something with an i3-7100u imo, newer platform and the hd 620 is nothing to shake a stick at. I believe you could also pick a decent one up for 500 NZD but i only did usd conversion and looked for laptops at and under $360, but i doubt there will be a 1:1 conversion of that sort while buying in NZ...
I'm just going to assume it's possible and give my endorsements:
It will be more efficient and run cooler than the latitude, cheap old laptops with dedicated gpu's tend to run at relatively scorching temperatures. What does that mean? Well it means your i5-4200u (which has 2 cores and 4 threads just like the i3-7100u, do not let the i5 name fool you) will be running at base clock almost all the time in games, not only due to cpu load which on haswell turbo boost tech means you go down to base clock after >50% cpu utilization, but maybe even when utilization is lower than that because of heat generated between it and the 740m. That brings it down to 1.6ghz.
Userbenchmark and Passmark scores do not take this into account because cpu and gpu tests are ran separately, not at all the kind of scenario you'll encounter in games.
At this point it's worth mentioning that the i3-7100u has no turbo boost, but its base clock of 2.4ghz which is obviously much higher than the 4200u's, which turbos just 200mhz higher in scenarios where cpu load and heat are low, which due to the slight ipc difference only puts it on par or slightly faster than the 7100u for stuff like web browsing. That consistent performance of 2.4ghz is much more desirable from the kaby lake i3, especially in these games which won't allow the dual core i5 to turbo very often.
Does this really matter, though? I would say... probably not. The heat matters yes but I believe that in these games you will be gpu bottlenecked in almost every case on both machines, so even with the haswell i5 being slower than the kaby lake i3, it comes down to gpu horsepower.
I've looked at various benchmarks and it seems the hd 620 and gt 740m are essentially equal. It would appear the 740m has a 1 fps average advantage in GTA 5 and that game is far more demanding than any of the ones you listed. Diablo 3 is probably the highest requirement one out of the bunch and I ran it on an old c2d and 8800 gts just fine back when it first came out (barring CSGO if you're competitive and need those big dick 300 fps's, neither cpu's are fast enough for that even if you go 800x600 low). Aside from that, they trade blows back and forth a lot.
You won't be pushing 300 fps in csgo by any means, but it should be well over 100. League of legend would also be easy for it.
So what really sets an i3-7100u and that latitude apart is not the performance they will attain in the games you listed, which I think will be virtually identical, it's the amount of heat generated and the difference in platform age. Heat can affect reliability and age of the platform could concievable affect compatibility with programs requiring newer instructions or for example kaby lake's DRM hardware decoder for netflix, the 740m is also designed for dx11, seems nvidia shoehorned in dx12 support in later but I wouldn't expect it to outperform the hd 620 in that regard. I dont think dx12 is taking the market by storm any time soon anyway but everything is a consideration.
Good luck with whatever you decide to go with. And be sure to get the fastest RAM you can if you go with a i3-7100u because the cpu and gpu share the same memory bus, you're not likely to hit a bandwidth wall on ddr4 with such a chip even if you get the laptop with the slowest RAM on the market but still... better safe than sorry right? I've never had an igpu before but the idea of my shaders and cpu cores sharing the same memory skeeves me out a bit for some reason.
This post was edited by DCSS on Jun 15 2017 05:10am