Hi!
"It's 87" means it's max detected or average value? If average - it seems quite not right. But just quite.
For this laptop average 80-85 under heavy load is "normal" - I have such temp too (in Dark souls III, for example). This model, unfortunately,
heats up too fast.
Tech support says 85 is max recommended temps, so, i think, 87 on peak is not so bad, but cooler is better, of course. Also, it starts throttling already at 82-83 C and because of this 87 is peak, not 90+. But it seems that even 80-85 is not so good in terms of laptop lifespan. You can lower temps for ~10C with disabling Intel Turbo Boost: Control Panel > Power Options > Change Plan Settings > Change Advanced Power Settings > Maximum processor state > set 99% (minimum should also be lower 100%). It will make processor operate on base frequency, but will also keep it from overheating (it became 73-75C , very rarely 80). This will not signaficantly reduce game peformance: in Dark Souls III it keeps fps 55-60 as it was at 100% maximum state, and only in one location, in leads to ~10 frame drop (1600x900at Max; however, 1920x1020 does not make noticeable difference, only ~5-7 fps).
Also, fan boost seems to be glitching, I met several threads here where people complain that maximasing fan speed even led to shutdown. My first laptop (also gl553vd) did so, and I managed to exchange it. Second seem to work correctly.
But what in your case is bothering me, is that i did not notice fps drops even while throttling. Check with Gaming Center, what are processors' core frequencies when you maximase fan speed to 5400? If you set 5400 with single displacement of the slider and then freqs go 799 Mhz and stay there - it's bad, try to exchange laptop.
Also, use smth like HWInfo64 and make a record of temp/voltage/freqs values via sensors mode.
