@Nabull You should look for a HQ-series or MQ-series (quad-cores) based mobile intel cpu equipped laptops while avoid the U-series (dual-cores.) HEVC encoding benefits greatly from AVX2 instruction set so a minimum of 4th gen should be sought like a i7-4710MQ (Haswell) which encoded Attack on Titans episode 1 under 50 minutes using x265 preset slow into 720p 10-bit. 6th-7th gen (i7-7700HQ for example) would be ideal. Go for a business or gaming class laptop for good build quality and adequate cooling and/or buy a chill mate as well.
Some links below based on quick searching to get an idea of what's out there.
Laptops https://www.amazon.com/Notebook-Computer-Quad-Core-i7-6700HQ-GeForce/dp/B01MR05UO2/ https://www.amazon.com/Acer-Aspire-15-i5-6300HQ-Display/dp/B01N8SI9I7/
https://www.amazon.com/Lastest-Computer-Quad-Core-i5-6300HQ-Bluetooth/dp/B06XZF5L68/ https://www.amazon.com/HoMei-i7-4710MQ-GeForce-Bluetooth-Keyboard/dp/B06Y2BMF9W/ http://store.hp.com/us/en/pdp/hp-power-pavilion-laptop----17t-x7n62av-1 https://www.notebookcheck.net/HP-Pavilion-17t-ab200-Notebook-Review.197952.0.html http://www.pro-star.com/index.php?r=product/configure&model=N855HJ
Laptops - Certified Refurbished (look and work like new)
i7-6820HQ $694.66 https://www.amazon.com/Dell-Latitude-i7-6820HQ-Certified-Refurbished/dp/B0727S6TKH/
i5-7300HQ $669.99 https://www.amazon.com/Acer-Windows-VX5-591G-5652-Certified-Refurbished/dp/B07286CT4Y/