I would like to play games with better performance than what I'm getting after updating to Kubuntu 16.04 LTS. Half the games are unplayable, sometimes to the level of nauseating due to low fps. I'm not entirely sure if my open-source radeon drivers are working as they're supposed to.

I realize that AMD dropped support for proprietary fglrx drivers some time ago and they were deprecated in 16.04 due to incompatibility with the newer xorg.

My main question is:

Can I run games in a separate xorg environment using the older xorg version that still has fglrx driver support in Kubuntu 16.04?

Ideally in a way that other software (like browser or IM) would still be running and kind of accessible. Like on a separate tty or something. In the really perfect case none of that would have any GPU performance spent on it (so not rendered I guess).

Alternatively I'm interested of any other clues to increasing my performance.

I guess switching to Ubuntu 14.04 is one of my options at the cost of having most of my software be of older versions.

My GPU is AMD Radeon HD 7670M in a Dell Inspiron 15 (5520)

lspci -nnk | grep -i vga -A3 output:

00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)

        Subsystem: Dell 3rd Gen Core processor Graphics Controller [1028:056a]

        Kernel driver in use: i915

        Kernel modules: i915

--

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Thames [Radeon HD 7500M/7600M Series] [1002:6840] (rev ff)

        Kernel driver in use: radeon

        Kernel modules: radeon

07:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller [10ec:8136] (rev 05)

sudo lshw -c video output:

  *-display               

       description: VGA compatible controller

       product: 3rd Gen Core processor Graphics Controller

       vendor: Intel Corporation

       physical id: 2

       bus info: pci@0000:00:02.0

       version: 09

       width: 64 bits

       clock: 33MHz

       capabilities: msi pm vga_controller bus_master cap_list rom

       configuration: driver=i915 latency=0

       resources: irq:28 memory:c1000000-c13fffff memory:b0000000-bfffffff ioport:4000(size=64)

Asking any additional information is also welcome.