Considering hardware for a gaming laptop. Not building my own, but found a great deal on a machine from last season still sporting a 4720HQ processor.
Comparing benchmarks between the Haswell 4720HQ and the Skylake 6700HQ seems to suggest they're roughly comparable. The 6700 is, on average, about 5% better but some sites, such as cpuboss, actually suggest the older chip is marginally faster. There are lots of benchmarks and I'm not sure which to trust as regards a machine intended primarily for gaming, but from speed alone the 6700 doesn't appear to be worthwhile.
However, speed isn't the only improvement in Haswell vs Skylake. Most of the others don't interest me. Better integrated graphics aren't much use in a machine with a dedicated GPU. The support for DDR4 isn't a big deal in a laptop where I'm unlikely to be upgrading the default RAM. The effeciency gains aren't helpful since I spend most of my time plugging in to a power socket.
The differences in connectivity though, could be a big deal, and that's support for Thunderbolt and USB 3.1.
About a year ago there was a big explosion in interest about Thunderbolt, partly because it offered the possibility of running desktop-grade GPUs as an external plug-in to laptops and all kinds of other cool stuff. Right now, I can't ascertain whether this has lead to any tangible use cases or is likely to. I'm not even entirely sure, to be honest, whether you can even buy non-Apple laptops with Thunderbolt ports, or how to find them (it seems to be referred to as USB Type-C in some places).
So, is it realistic to go looking for a Skylake laptop with Thunderbolt, with a view to plugging in some monstrous desktop GPU, or some other reason (are the benchmarks lying)? Or should I stick with Haswell for now?