Utilisation cpu instable

Bijour, voilà mon cpu est plutot instable en ce moment
je viens de formater et réinstaller windows, avant le cpu trainait autour des 8-10% d'utilisation (sans trop d'applications)
et maintenant, lorsque je démarre le pc il est parfois à 25% puis redescends à 3%, et quand je lance certaines applications (comme un lecteur video ou Steam) il grimpe pas mal, passe sans arret de 8 à 25%, et grimpe meme jusqu'à 40
en jeu, ca depasse quand meme pas les 50...
bon ca fait trop pas ramer le pc, j'ai regardé les températures, il est pas plus chaud qu'avant... mais ca m'embete quand meme, d'où ça pourrait venir ?

Voilà un rapport hijackthis, jsais pas si ça serviva :

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 14:00:11, on 25/09/2011
Platform: Unknown Windows (WinNT 6.01.3504)
MSIE: Internet Explorer v8.00 (8.00.7600.16839)
Boot mode: Normal

Running processes:
C:\Program Files (x86)\mes logiciels\rocket dock\RocketDock.exe
C:\Program Files (x86)\mes logiciels\avg\avgtray.exe
C:\Program Files\Common Files\LogiShrd\sp6\LU\LULnchr.exe
C:\Program Files\Common Files\LogiShrd\sp6\LU\LogitechUpdate.exe
C:\Program Files (x86)\Common Files\Realtime Soft\RTSHookInterop\x32\RTSHookInterop.exe
C:\Program Files (x86)\mes logiciels\mozilla firefox\firefox.exe
C:\Program Files (x86)\mes logiciels\mozilla firefox\plugin-container.exe
C:\Users\Max\Desktop\HiJackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page = C:\Windows\SysWOW64\blank.htm
R1 -
HKCU\Software\Microsoft\Windows\CurrentVersion\Int
ernet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
F2 - REG:system.ini: UserInit=userinit.exe
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files (x86)\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: WormRadar.com IESiteBlocker.NavFilter - {3CA2F312-6F6E-4B53-A66E-4E65E497C8C0} - C:\Program Files (x86)\mes logiciels\avg\avgssie.dll
O2 - BHO: URLRedirectionBHO - {B4F3A835-0E21-4959-BA22-42B3008E02FF} - C:\Program Files (x86)\MICROS~1\Office14\URLREDIR.DLL
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files (x86)\Java\jre6\bin\jp2ssv.dll
O4 - HKLM\..\Run: [AVG9_TRAY] C:\Program Files (x86)\MESLOG~1\avg\avgtray.exe
O4 - HKCU\..\Run: [RocketDock] "C:\Program Files (x86)\mes logiciels\rocket dock\RocketDock.exe"
O4 - Startup: Rainmeter.lnk = C:\Program Files (x86)\mes logiciels\rainmeter\Rainmeter.exe
O4 - Global Startup: UltraMon.lnk = ?
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\Program Files (x86)\MESLOG~1\MICROS~1\Office14\EXCEL.EXE/3000
O13 - Gopher Prefix:
O18 - Protocol: linkscanner - {F274614C-63F8-47D5-A4D1-FBDDE494F8D1} - C:\Program Files (x86)\mes logiciels\avg\avgpp.dll
O18 - Filter hijack: text/xml - {807573E5-5146-11D5-A672-00B0D022E945} - C:\Program Files (x86)\Common Files\Microsoft Shared\OFFICE14\MSOXMLMF.DLL
O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing)
O23 - Service: AMD External Events Utility - Unknown owner - C:\Windows\system32\atiesrxx.exe (file missing)
O23 - Service: AMD FUEL Service - Advanced Micro Devices, Inc. - C:\Program Files\ATI Technologies\ATI.ACE\Fuel\Fuel.Service.exe
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files (x86)\Common Files\Apple\Mobile Device Support\AppleMobileDeviceService.exe
O23 - Service: AVG E-mail Scanner (avg9emc) - AVG Technologies CZ, s.r.o. - C:\Program Files (x86)\mes logiciels\avg\avgemc.exe
O23 - Service: AVG WatchDog (avg9wd) - AVG Technologies CZ, s.r.o. - C:\Program Files (x86)\mes logiciels\avg\avgwdsvc.exe
O23 - Service: Service Bonjour (Bonjour Service) - Apple Inc. - C:\Program Files (x86)\Bonjour\mDNSResponder.exe
O23 - Service: @%SystemRoot%\system32\efssvc.dll,-100 (EFS) - Unknown owner - C:\Windows\System32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\fxsresm.dll,-118 (Fax) - Unknown owner - C:\Windows\system32\fxssvc.exe (file missing)
O23 - Service: Service de l'iPod (iPod Service) - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: @keyiso.dll,-100 (KeyIso) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: Logitech Bluetooth Service (LBTServ) - Logitech, Inc. - C:\Program Files\Common Files\LogiShrd\Bluetooth\lbtserv.exe
O23 - Service: @comres.dll,-2797 (MSDTC) - Unknown owner - C:\Windows\System32\msdtc.exe (file missing)
O23 - Service: @%SystemRoot%\System32\netlogon.dll,-102 (Netlogon) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\psbase.dll,-300 (ProtectedStorage) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\Locator.exe,-2 (RpcLocator) - Unknown owner - C:\Windows\system32\locator.exe (file missing)
O23 - Service: @%SystemRoot%\system32\samsrv.dll,-1 (SamSs) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%SystemRoot%\system32\snmptrap.exe,-3 (SNMPTRAP) - Unknown owner - C:\Windows\System32\snmptrap.exe (file missing)
O23 - Service: @%systemroot%\system32\spoolsv.exe,-1 (Spooler) - Unknown owner - C:\Windows\System32\spoolsv.exe (file missing)
O23 - Service: @%SystemRoot%\system32\sppsvc.exe,-101 (sppsvc) - Unknown owner - C:\Windows\system32\sppsvc.exe (file missing)
O23 - Service: Steam Client Service - Valve Corporation - C:\Program Files (x86)\Common Files\Steam\SteamService.exe
O23 - Service: TuneUp Utilities Service (TuneUp.UtilitiesSvc) - TuneUp Software - C:\Program Files (x86)\mes logiciels\tuneup 2010\TuneUpUtilitiesService64.exe
O23 - Service: @%SystemRoot%\system32\ui0detect.exe,-101 (UI0Detect) - Unknown owner - C:\Windows\system32\UI0Detect.exe (file missing)
O23 - Service: @%SystemRoot%\system32\vaultsvc.dll,-1003 (VaultSvc) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%SystemRoot%\system32\vds.exe,-100 (vds) - Unknown owner - C:\Windows\System32\vds.exe (file missing)
O23 - Service: @%systemroot%\system32\vssvc.exe,-102 (VSS) - Unknown owner - C:\Windows\system32\vssvc.exe (file missing)
O23 - Service: @%SystemRoot%\system32\Wat\WatUX.exe,-601 (WatAdminSvc) - Unknown owner - C:\Windows\system32\Wat\WatAdminSvc.exe (file missing)
O23 - Service: @%systemroot%\system32\wbengine.exe,-104 (wbengine) - Unknown owner - C:\Windows\system32\wbengine.exe (file missing)
O23 - Service: @%Systemroot%\system32\wbem\wmiapsrv.exe,-110 (wmiApSrv) - Unknown owner - C:\Windows\system32\wbem\WmiApSrv.exe (file missing)
O23 - Service: @%PROGRAMFILES%\Windows Media Player\wmpnetwk.exe,-101 (WMPNetworkSvc) - Unknown owner - C:\Program Files (x86)\Windows Media Player\wmpnetwk.exe (file missing)

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