I can offer you some assistance. I found a laptop similar to mine on PC Specialist, few parts are different but I think the model is near enough the same. I get good performance out of mine, around 3 hours battery life whilst messing around on After Effects and doing some light gaming, so I'm guessing between 1 and 2 hours when pure gaming on more high-spec games.
Link: https://www.pcspecialist.co.uk/notebooks/cosmosII-17/
Display: Full HD Widescreen
CPU: Intel® Core i5-4210M CPU @ 2.60GHz
RAM: 8Gb Kingston (Can't remember if it was the HYPER-X or standard)
Graphics Card: Nvidia GeForce 840M
HDD: 500Gb Serial ATA II
2nd HDD: None
DVD/Blu Ray Drive: 8x SATA DVD+R/RW/Dual Layer
Memory Card Reader: The only option there.
Thermal Paste: Arctic MX-4
Sound Card: Intel High 2 Channel High Definition Audio
Bluetooth/Wireless: 150Mbps (Top option)
Router: None
USB: The only option there.
Battery: The only battery type there (I bought 1).
Power lead: 1 UK power lead.
OS: Windows 7 Home Premium 64bit (Windows 8 can get bent)
Office Software: None
Anti-Virus: Bullguard
All the rest of the options default.
All that comes to £621.00, which is a pretty good price if you ask me. Good value for money. I reccommend this build to anyone looking for a nice mid-high end portable gaming rig. Renders things with ease on After Effects aswell (Although I don't do crazy CGI, just minor post-production stuff that never gets published. So I don't know how it'll handle active 3D rendering, I presume well).
The only problem is the touchpad. It lacks distinct buttons. So you kind of have to guess where the right and left mouse buttons are, and your mouse clicks can get a little inaccurate because the mouse buttons are actually a part of the touchpad. I'd just use a mouse, but I rarely have the space to use a mouse aswell, so I just make-do for now.
Hope this helps in your descisions.