Same issue here after updating. WindowServer process just keep on hogging memory with time without ever releasing it until it's forcefully restarted (logout or reboot).
I have no external monitor, and while I use a scaled resolution I can reproduce it with the regular one.
Here's an EtreCheck's report, in case it could be useful:
EtreCheck version: 3.4.5 (455)
Report generated 2017-09-28 18:53:11
Download EtreCheck from https://etrecheck.com
Runtime: 2:01
Performance: Excellent
Click the [Lookup] links for more information from Apple Support Communities.
Click the [Details] links for more information about that line.
Problem: No problem - just checking
Hardware Information: ⓘ
MacBook Pro (Retina, 15-inch, Mid 2015)
[Technical Specifications] - [User Guide] - [Warranty & Service]
MacBook Pro - model: MacBookPro11,5
1 2,5 GHz Intel Core i7 (i7-4870HQ) CPU: 4-core
16 GB RAM Not upgradeable
BANK 0/DIMM0
8 GB DDR3 1600 MHz ok
BANK 1/DIMM0
8 GB DDR3 1600 MHz ok
Handoff/Airdrop2: supported
Wireless: en0: 802.11 a/b/g/n/ac
Battery: Health = Normal - Cycle count = 446
iCloud Quota: 4.62 GB available
Video Information: ⓘ
AMD Radeon R9 M370X - VRAM: 2 GB
Intel Iris Pro - VRAM: 1536 MB
Color LCD 3360 x 2100
Disk Information: ⓘ
APPLE SSD SM0512G disk0: (500,28 GB) (Solid State - TRIM: Yes)
[Show SMART report]
EFI (disk0s1 - MS-DOS FAT32) <not mounted> [EFI]: 210 MB
(disk0s2) <not mounted> [APFS Container]: 500.07 GB
USB Information: ⓘ
USB30Bus
Apple Inc. Apple Internal Keyboard / Trackpad
Broadcom Corp. Bluetooth USB Host Controller
Thunderbolt Information: ⓘ
Apple Inc. thunderbolt_bus
Virtual disks: ⓘ
Macintosh HD (disk1s1 - APFS) / [Startup]: 500.07 GB (340.46 GB free)
Physical disk: disk0s2 500.07 GB (340.46 GB free)
(disk1s2) <not mounted> [Preboot]: 500.07 GB
Physical disk: disk0s2 500.07 GB
(disk1s3) <not mounted> [Recovery]: 500.07 GB
Physical disk: disk0s2 500.07 GB
(disk1s4) /private/var/vm [VM]: 500.07 GB
Physical disk: disk0s2 500.07 GB
System Software: ⓘ
macOS High Sierra 10.13 (17A365) - Time since boot: about 17 hours
Configuration files: ⓘ
/etc/hosts - Count: 15
Gatekeeper: ⓘ
Mac App Store and identified developers
System Launch Agents: ⓘ
[not loaded] 9 Apple tasks
[loaded] 167 Apple tasks
[running] 112 Apple tasks
System Launch Daemons: ⓘ
[not loaded] 37 Apple tasks
[loaded] 183 Apple tasks
[running] 109 Apple tasks
Launch Agents: ⓘ
[not loaded] com.adobe.AAM.Updater-1.0.plist (Adobe Systems, Inc. - installed 2016-12-25) [Lookup]
[running] com.bjango.istatmenus.agent.plist (Bjango Pty Ltd - installed 2017-09-27) [Lookup]
[running] com.bjango.istatmenus.status.plist (Bjango Pty Ltd - installed 2017-09-27) [Lookup]
[loaded] com.oracle.java.Java-Updater.plist (? 9c0d8d87 72ac4dde - installed 2017-08-03) [Lookup]
[loaded] org.macosforge.xquartz.startx.plist (Apple Inc. - XQuartz - installed 2016-10-26) [Lookup]
Launch Daemons: ⓘ
[loaded] com.adobe.ARMDC.Communicator.plist (Adobe Systems, Inc. - installed 2017-01-10) [Lookup]
[loaded] com.adobe.ARMDC.SMJobBlessHelper.plist (Adobe Systems, Inc. - installed 2017-01-10) [Lookup]
[running] com.adobe.adobeupdatedaemon.plist (Adobe Systems, Inc. - installed 2016-12-25) [Lookup]
[running] com.adobe.agsservice.plist (Adobe Systems, Inc. - installed 2017-05-29) [Lookup]
[loaded] com.adobe.fpsaud.plist (? 2afb3af7 4898e928 - installed 2017-08-29) [Lookup]
[not loaded] com.apple.installer.cleanupinstaller.plist (? 1963bf56 0 - installed 2017-09-25)
[loaded] com.barebones.authd.plist (Bare Bones Software, Inc. - installed 2016-04-03) [Lookup]
[running] com.bjango.istatmenus.daemon.plist (Bjango Pty Ltd - installed 2017-09-27) [Lookup]
[loaded] com.bjango.istatmenus.installerhelper.plist (Bjango Pty Ltd - installed 2017-09-27) [Lookup]
[loaded] com.microsoft.autoupdate.helper.plist (Microsoft Corporation - installed 2017-09-13) [Lookup]
[loaded] com.oracle.java.Helper-Tool.plist (Shell Script e3fefdd2 - installed 2017-07-22) [Lookup]
[running] com.tclementdev.timemachineeditor.scheduler.plist (Thomas CLEMENT - installed 2017-09-20) [Lookup]
[loaded] org.macosforge.xquartz.privileged_startx.plist (Apple Inc. - XQuartz - installed 2016-10-26) [Lookup]
User Launch Agents: ⓘ
[not loaded] com.adobe.AAM.Updater-1.0.plist (Adobe Systems, Inc. - installed 2016-12-25) [Lookup]
[loaded] com.dropbox.DropboxMacUpdate.agent.plist (Dropbox, Inc. - installed 2017-08-10) [Lookup]
[loaded] com.google.keystone.agent.plist (Google, Inc. - installed 2017-07-10) [Lookup]
User Login Items: ⓘ
ClipMenu Application
(/Applications/ClipMenu.app)
Backup ans Sync Application
(/Applications/Cloud/Backup and Sync.app)
Cinch Application
(/Applications/Cinch.app)
gfxCardStatus Application
(/Applications/gfxCardStatus.app)
Dropbox Application
(/Applications/Cloud/Dropbox.app)
Internet Plug-ins: ⓘ
AdobeAAMDetect: 3.0.0.0 (installed 2016-12-25) [Lookup]
FlashPlayer-10.6: 27.0.0.130 (installed 2017-09-12) [Lookup]
QuickTime Plugin: 7.7.3 (installed 2017-09-21)
AdobePDFViewerNPAPI: 15.010.20060 (installed 2016-02-26) [Lookup]
AdobePDFViewer: 15.010.20060 (installed 2016-02-26) [Lookup]
Flash Player: 27.0.0.130 (installed 2017-09-12) [Lookup]
VLC Plugin: 2.2.7 (installed 2017-08-14) [Lookup]
JavaAppletPlugin: Java 8 Update 144 build 01 (installed 2017-08-03) Check version
Safari Extensions: ⓘ
[enabled] uBlock Origin - Chris Aljoudi/Raymond Hill - https://www.github.com/el1t/uBlock-Safari (installed 2017-08-09)
[enabled] Search Alias - Damian Carrillo - http://damiancarrillo.com/blog/search-alias-a-safari-extension/ (installed 2016-12-21)
[enabled] Safarikai - James Chen - http://ashchan.github.io/safarikai/ (installed 2017-08-09)
[enabled] Tampermonkey - Jan Biniok - http://tampermonkey.net (installed 2017-08-09)
3rd Party Preference Panes: ⓘ
RCDefaultApp (installed 2009-09-20) [Lookup]
Flash Player (installed 2017-08-29) [Lookup]
FUSE (installed 2017-09-21) [Lookup]
Java (installed 2017-08-03) [Lookup]
Time Machine: ⓘ
Mobile backups: OFF
Auto backup: NO - Auto backup turned off
Volumes being backed up:
Macintosh HD: Disk size: 500.07 GB Disk used: 159.61 GB
Destinations:
Data [Network]
Total size: 3.00 TB
Total number of backups: 55
Oldest backup: 30/03/16, 03:54
Last backup: 27/09/17, 23:44
Size of backup disk: Excellent
Backup size 3.00 TB > (Disk size 500.07 GB X 3)
Top Processes by CPU: ⓘ
25% plugin-container
25% firefox
17% WindowServer
6% kernel_task
3% hidd
Top Processes by Memory: ⓘ
3.13 GB WindowServer
1.52 GB firefox
1.40 GB kernel_task
627 MB plugin-container
533 MB plugin-container
Top Processes by Network Use: ⓘ
Input Output Process name
836 KB 915 KB firefox
1 MB 43 KB Mail
1 MB 126 KB mDNSResponder
374 KB 507 KB Dropbox
245 KB 185 KB Transmission
Top Processes by Energy Use: ⓘ
19.34 firefox
16.10 plugin-container
6.92 WindowServer
2.58 plugin-container
Virtual Memory Information: ⓘ
2.38 GB Available RAM
482 MB Free RAM
13.62 GB Used RAM
1.91 GB Cached files
228 MB Swap Used
Software installs: ⓘ
TimeMachineEditor: (installed 2017-09-03)
FUSE for macOS: (installed 2017-09-03)
Microsoft OneNote: 15.38 (installed 2017-09-08)
Adobe Flash Player: (installed 2017-09-12)
Install information may not be complete.
Diagnostics Information: ⓘ
2017-09-27 22:37:12 WindowServer Crash [Open]
Cause: StartTime:2017-09-27 20:40:26
GPU:IG&AMD
MetalDevice for accelerator(0x3827): 0x7fde7fc3eb78 (MTLDevice: 0x7fde8189a600)
MetalDevice for accelerator(0x5307): 0x7fde7fd19f68 (MTLDevice: 0x7fde81888000)
IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/IGPU@2/AppleIntelFramebu ffer@0
abort() called
terminating with uncaught exception of type std::__1::system_error: mutex lock failed: Invalid argument
2017-09-27 20:40:36 corespotlightd Crash [Open]
Cause: [0x700002dd3000] Finalizing journal 0x7fdd40a00ed0 0x108dc5000 100000
Initializing
2017-09-26 12:37:10 installd High CPU use [Open] [Details]
2017-09-26 10:53:27 iStatMenusDaemon Crash [Open]
Cause: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]'
abort() called
terminating with uncaught exception of type NSException