Sorry about the delay, been very busy.
All the drivers, firmwares, BIOS etc, are up-to-date. I've tried reflashing the keyboard's firmware, and re-installing CUE.
Sys Info:
::: BIOS
Name : BIOS Date: 03/03/16 23:53:25 Ver: 04.06.05
Manufacturer : American Megatrends Inc.
Version : ALASKA - 1072009
::: Motherboard
Product name : Z97P-D3
Manufacturer : Gigabyte Technology Co., Ltd.
::: CPU
Name : Intel® Core i7-4790K CPU @ 4.00GHz
Description : Intel64 Family 6 Model 60 Stepping 3
Frequency : 4001
Number of cores : 4
Number of logical processors : 8
::: Physical memory
Manufacturer : Kingston
Speed : 2400
Form factor : DIMM
Memory type : Unknown
Capacity : 8192 MB
Manufacturer : Kingston
Speed : 2400
Form factor : DIMM
Memory type : Unknown
Capacity : 8192 MB
Manufacturer : Kingston
Speed : 2400
Form factor : DIMM
Memory type : Unknown
Capacity : 8192 MB
Manufacturer : Kingston
Speed : 2400
Form factor : DIMM
Memory type : Unknown
Capacity : 8192 MB
::: USB Controller
Name : Intel® USB 3.0 eXtensible Host Controller - 1.0 (Microsoft)
Manufacturer : Generic USB xHCI Host Controller
Name : Standard Enhanced PCI to USB Host Controller
Manufacturer : (Standard USB Host Controller)
Name : Standard Enhanced PCI to USB Host Controller
Manufacturer : (Standard USB Host Controller)
::: OS
Name : Microsoft Windows 10 Pro
Architecture : 64-bit
Service pack version, major : 0
Service pack version, minor : 0
::: User properties
Is run under administrator : no
User has administrator privileges : yes
::: Video hardware
Adapter name : NVIDIA GeForce GTX 970
Driver files : nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um,nvwgf2um
Driver version : 10.18.13.6472
RAM : 1 MB
Max refresh rate : 75
Min refresh rate : 59
::: Displays
Name : Dell U2413(Digital)
Resolution : 1920 x 1200
Refresh rate : 59
Color depth : 32
Connected to : NVIDIA GeForce GTX 970
::: Storage
Model : Patriot Memory USB Device
Interface type : USB
Manufacturer : (Standard disk drives)
Size : 57.5985 GB
Model : WDC WD6400AAKS-75A7B2
Interface type : IDE
Manufacturer : (Standard disk drives)
Size : 596.17 GB
Model : Crucial_CT120M500SSD1
Interface type : IDE
Manufacturer : (Standard disk drives)
Size : 111.788 GB
::: Chipset
Short name : Intel® 9 Series Chipset Family SMBus Host Controller - 8CA2
Name : Intel® 9 Series Chipset Family SMBus Host Controller - 8CA2
Manufacturer : INTEL
Short name : Intel® 9 Series Chipset Family PCI Express Root Port 1 - 8C90
Name : Intel® 9 Series Chipset Family PCI Express Root Port 1 - 8C90
Manufacturer : INTEL
Service : pci
Short name : Intel® Z97 Chipset LPC Controller - 8CC4
Name : Intel® Z97 Chipset LPC Controller - 8CC4
Manufacturer : INTEL
Service : msisadrv
Short name : Intel® 9 Series Chipset Family PCI Express Root Port 3 - 8C94
Name : Intel® 9 Series Chipset Family PCI Express Root Port 3 - 8C94
Manufacturer : INTEL
Service : pci
Short name : Intel® 9 Series Chipset Family PCI Express Root Port 4 - 8C96
Name : Intel® 9 Series Chipset Family PCI Express Root Port 4 - 8C96
Manufacturer : INTEL
Service : pci
::: Corsair devices
Device name : Corsair Corsair K95 RGB Gaming Keyboard 02021025AEAA1004550126BBF5001943
Status : DeviceConnected (0x1)
Working speed : Full Speed (0x1)
Connected to : USB xHCI Compliant Host Controller
→ Root Hub
→ Port 9
USB VID : 0x1b1c
USB PID : 0x1b11
Hub driver : Standard, USB 3.0
::: Keyboard layouts
Language ID : 0x2057
Layout ID : 0x2057
Name : English