Hello,
Whenever I try to play any source game, after a period of time it will crash. The period of crashing is random, as it can crash in a few minutes, or take half an hour. I can't switch to a TTY, or use SYSRQ.

Things I have tried to do:

• Disable Steam In-Game Overlay,
• Run Steam without runtime,
• Try three different desktop environments,
• Use prerelease of source games,
• Downgrade Catalyst drivers,
• Dmesg, Journalctl, Xorg log, they show no errors.
• SSH works during the freeze.
• Added more swap space to see if it's a memory leak.
• Compositing off.
• Play in Windowed mode.

As you correctly are thinking, none of those things helped.

It is impossible to get a backtrace as it freezes, and trying to write to a file also cuts off. I will try starting Steam through SSH with the DISPLAY variable in a moment.

Processor Information:
    Vendor:  GenuineIntel
    CPU Family:  0x6
    CPU Model:  0x17
    CPU Stepping:  0xa
    CPU Type:  0x0
    Speed:  2663 Mhz
    4 logical processors
    4 physical processors
    HyperThreading:  Unsupported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Unsupported
    SSE41:  Supported
    SSE42:  Unsupported

Network Information:
    Network Speed:  

Operating System Version:
    Linux (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.12.6-1-ARCH
    X Server Vendor:  The X.Org Foundation
    X Server Release:  11405000
    X Window Manager:  KWin
    Steam Runtime Version:  steam-runtime-release_2013-10-23

Video Card:
    Driver:  ATI Technologies Inc. AMD Radeon HD 7700 Series   

    Driver Version:  4.3.12618 Compatibility Profile Context 13.101
    OpenGL Version: 4.3
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 60 Hz
    VendorID:  0x1002
    DeviceID:  0x683f
    Number of Monitors:  1
    Number of Logical Video Cards:  1
    Primary Display Resolution:  1920 x 1080
    Desktop Resolution: 1920 x 1080
    Primary Display Size: 20.08" x 11.42"  (23.07" diag)
                                            51.0cm x 29.0cm  (58.6cm diag)
    Primary VRAM Not Detected

Sound card:
    Audio device: Realtek ALC662 rev1

Memory:
    RAM:  3957 Mb

Miscellaneous:
    UI Language:  English
    LANG:  en_US.UTF-8
    Microphone:  Not set
    Total Hard Disk Space Available:  606884 Mb
    Largest Free Hard Disk Block:  199105 Mb

Installed software:

Recent Failure Reports: