The HDD should never cost you any fps, unless you have so little RAM that the entire game needs to be in the swap file, in which case you'd not have frames per second but rather frames per minute.
It can lead to somewhat longer loading times or very short hiccups at worst, but I got plenty of games on HDDs and they usually run just fine.
In open world titles, the loading times usually occur just once and maybe a bit during quick travel. SSDs can improve that, but in many games the reduction is relatively small and only noticeable during the first start before the files are cached in your RAM.

Upgrading the RAM could help, depending on the title, but with the CPU and GPU I still wouldn't expect every modern game to run just splendidly. E.g. AC:Origins needs at the very least 4 cores to run, those 4 cores in the notebook are also not clocked very high and potentially limited by the cooling solution etc. So it might lead to stutter even if every other component were not an issue. With the GTX 1050 4GB I also wouldn't set the graphical quality anywhere far beyond ~medium in 1080p for decent fps in that game. That's assuming the RAM is not an issue (anymore).

Of course there are also more and less demanding games, both for the CPU and GPU. I recently noticed that Cities:Skylines maxes out all four cores and I got only ~25-30fps in that savegame (bigger city, but not all that big) and my CPU (i5 6600) is a bit faster than the notebook thingie there.

On the other hand, Paradox games like Stellaris only really use one core and then lag on every CPU because even an i7 8700K will be easily maxed out on one single core after a while. Witcher 3 is relatively easy on the CPU, but you need a good GPU, etc.

It all depends on what you want to play. the GTX 1050 is NVidia's entry level GPU, I wouldn't call it future-proof by any means, especially the 4GB VRAM are lowest end nowadays, even 8GB might be considered low in two years time.