Merry Christmas everyone. There's plenty of threads of this issue on the internet, and I'm just going to list what I've tried:

Closing all applications
Virus scan (Malwarebytes and Defender offline scan)
Driver Factory reset
DDU

The curious thing is it's only GPU-Z that's listing the usage. Task Manager says my GPU is at 0% and fluctuates like normal, but my GPU is clearly climbing to over 70C and my memory and core clock are maxed. Sometimes a restart fixes the issue. Even then, after I close a game the GPU often stays at 100%.

Driver version: 17.12.2.

Here's a look at Process Explorer:
Code:
Process    CPU    Private Bytes    Working Set    PID    Description    Company Name    GPU
System Idle Process    96.92    52 K    8 K    0            
System    0.09    156 K    68 K    4            
 Interrupts    0.18    0 K    0 K    n/a    Hardware Interrupts and DPCs        
 smss.exe        476 K    1,196 K    448            
 Memory Compression        296 K    39,188 K    1980            
csrss.exe        1,880 K    5,036 K    604            
wininit.exe        1,420 K    6,540 K    716            
 services.exe    < 0.01    4,752 K    9,376 K    788            
  svchost.exe        932 K    3,872 K    920    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe    < 0.01    9,152 K    24,256 K    952    Host Process for Windows Services    Microsoft Corporation    
   ShellExperienceHost.exe    Suspended    33,804 K    94,500 K    8080    Windows Shell Experience Host    Microsoft Corporation    
   SearchUI.exe    < 0.01    99,552 K    163,200 K    7840    Search and Cortana application    Microsoft Corporation    
   RuntimeBroker.exe        5,368 K    21,492 K    3872    Runtime Broker    Microsoft Corporation    
   RuntimeBroker.exe        6,424 K    21,964 K    8296    Runtime Broker    Microsoft Corporation    
   SettingSyncHost.exe    < 0.01    9,188 K    22,252 K    8492    Host Process for Setting Synchronization    Microsoft Corporation    
   dllhost.exe        2,268 K    10,292 K    7432    COM Surrogate    Microsoft Corporation    
   RuntimeBroker.exe        8,400 K    40,284 K    7764    Runtime Broker    Microsoft Corporation    
   ApplicationFrameHost.exe        11,684 K    29,104 K    9472    Application Frame Host    Microsoft Corporation    
   WmiPrvSE.exe    0.14    9,188 K    18,892 K    9436            
   WinStore.App.exe    Suspended    25,292 K    61,124 K    8832    Store    Microsoft Corporation    
   RuntimeBroker.exe        4,724 K    19,008 K    10740    Runtime Broker    Microsoft Corporation    
   WindowsInternal.ComposableShell.Experiences.TextInput.InputApp.exe        17,292 K    60,332 K    10104    WindowsInternal.ComposableShell.Experiences.TextInput.InputApp.exe    Microsoft Corporation    
   RuntimeBroker.exe        1,372 K    6,556 K    3944    Runtime Broker    Microsoft Corporation    
   smartscreen.exe        9,960 K    15,620 K    7044    Windows Defender SmartScreen    Microsoft Corporation    
  svchost.exe    < 0.01    5,464 K    11,260 K    108    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,076 K    7,304 K    492    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,064 K    9,744 K    1164    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,780 K    11,240 K    1212    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,504 K    6,048 K    1252    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        5,984 K    15,292 K    1340    Host Process for Windows Services    Microsoft Corporation    
   taskhostw.exe        26,204 K    36,820 K    4756    Host Process for Windows Tasks    Microsoft Corporation    
   taskhostw.exe    < 0.01    6,608 K    17,872 K    10148            
  svchost.exe        2,580 K    10,836 K    1376    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe    < 0.01    12,748 K    15,460 K    1392    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        4,588 K    8,736 K    1468    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,448 K    9,052 K    1520    Host Process for Windows Services    Microsoft Corporation    
   sihost.exe        5,840 K    24,020 K    6272    Shell Infrastructure Host    Microsoft Corporation    
  atiesrxx.exe        1,400 K    5,968 K    1544    AMD External Events Service Module    AMD    
   atieclxx.exe    0.02    2,476 K    11,148 K    1896            
   DSEManager.exe        2,256 K    9,212 K    1928            
  svchost.exe        2,320 K    7,424 K    1572    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        4,120 K    11,040 K    1688    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,748 K    8,716 K    1744    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe    < 0.01    2,420 K    12,236 K    1832    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,276 K    5,816 K    1840    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,892 K    7,760 K    1852    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,792 K    8,300 K    1976    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,120 K    8,408 K    2040    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,776 K    10,016 K    556    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        3,776 K    13,420 K    2080    Host Process for Windows Services    Microsoft Corporation    
   audiodg.exe        7,188 K    12,452 K    9356            
  svchost.exe        4,184 K    11,956 K    2136    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,292 K    8,980 K    2180    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe    < 0.01    3,236 K    8,228 K    2188    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,620 K    6,184 K    2196    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,544 K    11,828 K    2256    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,840 K    7,288 K    2352    Host Process for Windows Services    Microsoft Corporation    
  spoolsv.exe        6,716 K    16,232 K    2376    Spooler SubSystem App    Microsoft Corporation    
  svchost.exe        12,380 K    22,672 K    2484    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,008 K    8,176 K    2560    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,520 K    7,424 K    2792    Host Process for Windows Services    Microsoft Corporation    
   dasHost.exe        15,696 K    26,516 K    3244            
  svchost.exe    0.11    6,840 K    15,588 K    2800    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        3,548 K    12,764 K    2808    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        23,764 K    33,400 K    2816    Host Process for Windows Services    Microsoft Corporation    
  PnkBstrA.exe    < 0.01    1,308 K    6,784 K    2824            
  svchost.exe        8,384 K    25,104 K    2832    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,576 K    6,576 K    2840    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        4,172 K    19,268 K    2844    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,324 K    5,756 K    2856    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,916 K    8,040 K    2864    Host Process for Windows Services    Microsoft Corporation    
  NST.exe    < 0.01    7,292 K    19,764 K    2992    Norton Identity Safe    Symantec Corporation    
   NST.exe        8,368 K    15,128 K    7132            
  SecurityHealthService.exe        4,136 K    16,044 K    3024    Windows Security Health Service    Microsoft Corporation    
  MsMpEng.exe    0.03    154,780 K    190,008 K    2156    Antimalware Service Executable    Microsoft Corporation    
  svchost.exe        1,284 K    5,412 K    3156    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,360 K    9,072 K    3196    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        3,740 K    14,180 K    3260    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        26,096 K    39,612 K    3344    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,640 K    6,684 K    3808    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,980 K    8,848 K    3984    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        3,372 K    12,508 K    3992    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,708 K    9,732 K    4036    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,696 K    8,120 K    4288    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,708 K    7,176 K    4476    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,196 K    11,908 K    4568    Host Process for Windows Services    Microsoft Corporation    
  SearchIndexer.exe        34,836 K    38,304 K    5764    Microsoft Windows Search Indexer    Microsoft Corporation    
  svchost.exe        2,476 K    11,908 K    6152    Host Process for Windows Services    Microsoft Corporation    
  NisSrv.exe    < 0.01    14,280 K    10,984 K    6700    Microsoft Network Realtime Inspection Service    Microsoft Corporation    
  svchost.exe    < 0.01    6,284 K    19,704 K    5812    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        5,924 K    29,900 K    4252    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        3,156 K    12,660 K    7040    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        1,796 K    8,024 K    7348    Host Process for Windows Services    Microsoft Corporation    
   ctfmon.exe    < 0.01    3,660 K    17,124 K    7420            
   TabTip.exe    0.05    9,304 K    30,636 K    10060            
    TabTip32.exe        1,324 K    5,156 K    4008            
  svchost.exe        1,364 K    6,056 K    9096    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        3,756 K    8,292 K    9180    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        6,344 K    18,084 K    9156    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe    0.01    4,588 K    15,896 K    2960    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,128 K    8,608 K    2092    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        5,700 K    22,104 K    7936    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        3,476 K    14,804 K    8292    Host Process for Windows Services    Microsoft Corporation    
  svchost.exe        2,020 K    6,980 K    10968    Host Process for Windows Services    Microsoft Corporation    
  SteamService.exe    < 0.01    10,936 K    15,736 K    2616    Steam Client Service    Valve Corporation    
 lsass.exe    < 0.01    6,560 K    16,152 K    808    Local Security Authority Process    Microsoft Corporation    
 fontdrvhost.exe        11,172 K    14,064 K    944            
csrss.exe    0.10    4,488 K    5,252 K    724            
winlogon.exe        2,432 K    10,004 K    868            
 fontdrvhost.exe        17,760 K    27,524 K    728            
 dwm.exe    0.32    85,756 K    58,492 K    1096            
explorer.exe    0.02    123,320 K    135,560 K    7484    Windows Explorer    Microsoft Corporation    
 MSASCuiL.exe        2,048 K    10,028 K    8672    Windows Defender notification icon    Microsoft Corporation    
 Steam.exe    0.10    85,948 K    148,804 K    1764    Steam Client Bootstrapper    Valve Corporation    
  steamwebhelper.exe    < 0.01    37,744 K    89,308 K    10276    Steam Client WebHelper    Valve Corporation    
   steamwebhelper.exe        12,208 K    19,612 K    856    Steam Client WebHelper    Valve Corporation    
   steamwebhelper.exe        26,088 K    39,516 K    6788    Steam Client WebHelper    Valve Corporation    
 GPU-Z.exe    0.04    21,172 K    15,220 K    10352            
 firefox.exe    0.11    151,992 K    216,672 K    5372    Firefox    Mozilla Corporation    
  firefox.exe    0.14    48,484 K    52,436 K    3492    Firefox    Mozilla Corporation    0.12
  firefox.exe    0.49    255,168 K    261,984 K    5428    Firefox    Mozilla Corporation    0.02
  firefox.exe        135,616 K    148,876 K    8320    Firefox    Mozilla Corporation    
 procexp64.exe    0.28    44,780 K    65,828 K    10256    Sysinternals Process Explorer    Sysinternals - www.sysinternals.com    
RadeonSettings.exe    < 0.01    404,872 K    33,016 K    8784    Radeon Settings: Host Application    Advanced Micro Devices, Inc.    
jusched.exe        1,428 K    7,404 K    8864    Java Update Scheduler    Oracle Corporation    
amddvr.exe    0.01    216,336 K    6,132 K    9172            
 amdow.exe        2,184 K    2,136 K    8856            
Discord.exe    0.05    38,680 K    76,636 K    10144    Discord    Discord Inc.    
 Discord.exe        53,388 K    71,492 K    6528    Discord    Discord Inc.    
 Discord.exe    0.36    132,588 K    213,672 K    9888    Discord    Discord Inc.    
Agent.exe    0.12    46,972 K    23,912 K    10636    Blizzard Update Agent    Blizzard Entertainment    
 conhost.exe        1,660 K    8,020 K    10600    Console Window Host    Microsoft Corporation    
 Battle.net.exe    0.21    140,580 K    176,284 K    1152    Blizzard Battle.net App    Blizzard Entertainment    
  Battle.net Helper.exe    0.06    32,624 K    54,848 K    11156            0.07
  Battle.net Helper.exe        47,180 K    69,928 K    10408
Edit: Well that didn't take long. The process 'AMD Relive: Host Application' is causing the issue. Guess I'm rolling back.