Created attachment 136066 [details]
screenshot of artifacts

I posted this bug on the valve github page first. They confirmed it, but asked
me to report it here.

https://github.com/ValveSoftware/csgo-osx-linux/issues/1567

Your system information

    System information from steam (Steam -> Help -> System Information) in a
gist:

Computer Information:
Manufacturer: Unknown
Model: Unknown
Form Factor: Desktop
No Touch Input Detected

Processor Information:
CPU Vendor: AuthenticAMD
CPU Brand: AMD Ryzen 5 1600X Six-Core Processor
CPU Family: 0x17
CPU Model: 0x1
CPU Stepping: 0x1
CPU Type: 0x0
Speed: 3600 Mhz
12 logical processors
6 physical processors
HyperThreading: Supported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Supported
SSE41: Supported
SSE42: Supported
AES: Supported
AVX: Supported
CMPXCHG16B: Supported
LAHF/SAHF: Supported
PrefetchW: Unsupported

Operating System Version:
Linux 4.x (64 bit)
Kernel Name: Linux
Kernel Version: 4.14.4-1-ARCH
X Server Vendor: The X.Org Foundation
X Server Release: 11905000
X Window Manager: KWin
Steam Runtime Version: steam-runtime-beta-release_2017-07-24

Video Card:
Driver: X.Org Radeon RX 580 Series (AMD POLARIS10 / DRM 3.19.0 / 4.14.4-1-ARCH,
LLVM 5.0.0)
Driver Version: 3.0 Mesa 17.2.5
OpenGL Version: 3.0
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 144 Hz
VendorID: 0x1002
DeviceID: 0x67df
Revision Not Detected
Number of Monitors: 1
Number of Logical Video Cards: 1
Primary Display Resolution: 1920 x 1080
Desktop Resolution: 1920 x 1080
Primary Display Size: 20.91" x 11.77" (23.98" diag)
53.1cm x 29.9cm (60.9cm diag)
Primary VRAM: 8171 MB

Sound card:
Audio device: ATI R6xx HDMI

Memory:
RAM: 16045 Mb

Miscellaneous:
UI Language: English
LANG: en_US.UTF-8
Total Hard Disk Space Available: 468427 Mb
Largest Free Hard Disk Block: 413929 Mb
VR Headset: None detected

Recent Failure Reports:

    Have you checked for system updates?: Yes and I have tried reinstalling
mesa and xf86-video-amdgpu

Please describe your issue in as much detail as possible:

There are artifacts in the rendered ground (so far I have only seen it on
de_cache). Two offset black squares with glitches appear around the player in
certain areas.

Steps for reproducing this issue:

    Join any game on de_cache
    Set shader level to "high" or "very high (default)"
    Look at artifacts in rendering the ground.