From this page: Intel graphics - ArchWiki
Disable Vertical Synchronization (VSYNC)
The intel-driver uses Triple Buffering for vertical synchronization; this allows for full performance and avoids tearing. To turn vertical synchronization off (e.g. for benchmarking) use this .drirc in your home directory:
### ~/.drirc
<device screen="0" driver="dri2">
<application name="Default">
<option name="vblank_mode" value="0"/>
</application>
</device>