Windows.old on cleaninstall ?


No matter how the windows.old was created you should not just delete it manually.
Use disk cleanup or storage cleanup to delete it as there will also be registry entries for the folder which Windows will remove when deleting the folder.
 

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Windows 11 Pro
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Windows 11 Pro
Do you know why?
It depends on how you do the clean install.


If you just reinstall over the existing windows partition, you do get a windows.old. Installer creates windows.old as it detects a windows installation before it reinstalls.

If you wipe all partitions at the main install page, you do not get the windows.old as there is no existing windows installation to detect.

edit: others say you get a blamk windows.old if you wipe partitions. Maybe that is a consequence of the new installer. Pretty sure the old installer did not do this. I will test in a vm.
 

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Windows 11 Pro + Win11 Canary VM.I9 13th gen i9-13900H 2.60 GHZ16 GB solderedIntegrated Intel Iris XE
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Windows 11 Pro + Win11 Canary VM.
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Laptop
Manufacturer/Model
ASUS Zenbook 14
CPU
I9 13th gen i9-13900H 2.60 GHZ
Motherboard
Yep, Laptop has one.
Memory
16 GB soldered
Graphics Card(s)
Integrated Intel Iris XE
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Realtek built in
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laptop OLED screen
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2880x1800 touchscreen
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1 TB NVME SSD (only weakness is only one slot)
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Internal + 65W thunderbolt USB4 charger
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Yep, got one
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Stella Artois (UK pint cans - 568 ml) - extra cost.
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Built in UK keybd
Mouse
Bluetooth , wireless dongled, wired
Internet Speed
900 mbs (ethernet), wifi 6 typical 350-450 mb/s both up and down
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Edge
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TPM 2.0, 2xUSB4 thunderbolt, 1xUsb3 (usb a), 1xUsb-c, hdmi out, 3.5 mm audio out/in combo, ASUS backlit trackpad (inc. switchable number pad)

Macrium Reflect Home V8
Office 365 Family (6 users each 1TB onedrive space)
Hyper-V (a vm runs almost as fast as my older laptop)
It creates the Windows.old folder even in a brand new VM, whose disk has never been used for anything. The folder is only mentioned in a couple of places in the registry, and it's totally fine to delete it on a new installation.
 

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Windows 11 Pro 25H212th Gen Core i7-1260P64 GB Micron PC4-25600Intel Iris Xe Graphics
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Windows 11 Pro 25H2
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PC/Desktop
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Intel NUC12WSHi7
CPU
12th Gen Core i7-1260P
Motherboard
NUC12WSBi7
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64 GB Micron PC4-25600
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Intel Iris Xe Graphics
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on-board Realtek HD Audio
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Dell U3219Q
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3840 x 2160
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Samsung SSD 990 PRO 1TB
Crucial MX500 2 TB
Antivirus
Microsoft Defender
It seems you didn't booted from the Win 11 USB installation drive and deleted ALL previous Windows partitions (EFI, MSR, C: and Recovery) and pointed to install on the unallocated space.

You will have a Windows.old folder if you didn't delete the Windows partitions and pointed to install on the C: partition.
Not me, I was responding to the original poster who claims there was a windows.old folder after a clean install
 

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Windows 11 Pro 25H2 (RP channel)
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MSI
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AMD Ryzen 7 9800X3D 8-core
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MEG X870E Godlike
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Logitech G915 X (wired)
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Logitech G903 with PowerPlay charger
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900Mb/sec
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Microsoft Edge
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Windows Defender
Running a 24H2 clean install with a blank disk will create an empty Windows.old. This is a byproduct of changes in the WinPE Setup client. 25H2 is just an upgraded version of 24H2, so it follows the same pattern.

If you bypass the new Setup client, and revert to using the legacy Setup, then no Windows.old is created. The folder is harmless because it's always empty after a clean install. You can remove it.
 

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Windows 7

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    Acemagic
    CPU
    Intel i7-14650HX
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    32 GB
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No matter how the windows.old was created you should not just delete it manually.
Use disk cleanup or storage cleanup to delete it as there will also be registry entries for the folder which Windows will remove when deleting the folder.
There are no references in the registry to windows.old, at least after a clean install other than to exclude that folder. You can safely delete it manually if you wish.
 

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    Win11 Pro 25H2 (RTM+)
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    PC/Desktop
    Manufacturer/Model
    Acemagic
    CPU
    Intel i7-14650HX
    Memory
    32 GB
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    No GPU - Built-in Intel Graphics
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    Integrated
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    Win11 Pro 25H2 (RTM+)Intel i7-1255U16 GBIntel Iris Xe Graphics
    Operating System
    Win11 Pro 25H2 (RTM+)
    Computer type
    Laptop
    Manufacturer/Model
    Lenovo ThinkBook 13x Gen 2
    CPU
    Intel i7-1255U
    Memory
    16 GB
    Graphics card(s)
    Intel Iris Xe Graphics
    Sound Card
    Realtek® ALC3306-CG codec
    Monitor(s) Displays
    13.3-inch IPS Display
    Screen Resolution
    WQXGA (2560 x 1600)
    Hard Drives
    2 TB 4 x 4 NVMe SSD
    PSU
    USB-C / Thunderbolt 4 Power / Charging
    Keyboard
    Backlit, spill resistant keyboard
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    Buttonless Glass Precision Touchpad
    Internet Speed
    1Gb Up / 1Gb Down
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    Edge
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    Windows Defender
    Other Info
    WiFi 6e / Bluetooth 5.1 / Facial Recognition / Fingerprint Sensor / ToF (Time of Flight) Human Presence Sensor
Correct. Only the new setup does this.
Yes - I just tested a clean install using new and old installer, deleting all partitions before installing.

1) New installer creates a blank windows.old (what a crappy pointless thing to do)

2) Old installer works as it always has i.e. it does not create a windows.old.

Frankly, I cannot see the point of the new installer. It just confuses things, and most websites showing how to do a clean install pre-date the new installer and are fine.

The new installer is a solution to a problem we never had!
 

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Windows 11 Pro + Win11 Canary VM.I9 13th gen i9-13900H 2.60 GHZ16 GB solderedIntegrated Intel Iris XE
OS
Windows 11 Pro + Win11 Canary VM.
Computer type
Laptop
Manufacturer/Model
ASUS Zenbook 14
CPU
I9 13th gen i9-13900H 2.60 GHZ
Motherboard
Yep, Laptop has one.
Memory
16 GB soldered
Graphics Card(s)
Integrated Intel Iris XE
Sound Card
Realtek built in
Monitor(s) Displays
laptop OLED screen
Screen Resolution
2880x1800 touchscreen
Hard Drives
1 TB NVME SSD (only weakness is only one slot)
PSU
Internal + 65W thunderbolt USB4 charger
Case
Yep, got one
Cooling
Stella Artois (UK pint cans - 568 ml) - extra cost.
Keyboard
Built in UK keybd
Mouse
Bluetooth , wireless dongled, wired
Internet Speed
900 mbs (ethernet), wifi 6 typical 350-450 mb/s both up and down
Browser
Edge
Antivirus
Defender
Other Info
TPM 2.0, 2xUSB4 thunderbolt, 1xUsb3 (usb a), 1xUsb-c, hdmi out, 3.5 mm audio out/in combo, ASUS backlit trackpad (inc. switchable number pad)

Macrium Reflect Home V8
Office 365 Family (6 users each 1TB onedrive space)
Hyper-V (a vm runs almost as fast as my older laptop)
If you don't delete Windows.old, then a cleanmgr task should remove it after 10 days. Like what happens after a legitimate Windows upgrade.
 

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Windows 7
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Windows 7
If you don't delete Windows.old, then a cleanmgr task should remove it after 10 days. Like what happens after a legitimate Windows upgrade.
I tried to delete the blank windows.old using disk cleanup as I have always done for years but for strangely for some reason the blank windows.old folder would not get deleted.

So I am not confident the 10 day removal will work.

Even more strangely, I just used delete from File Explorer and it got immediately deleted to the recycle bin. Normally, this does not work due to file permissions.

The simplest way to avoid this sillyness is to use the old installer, not the new one.
 

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Windows 11 Pro + Win11 Canary VM.I9 13th gen i9-13900H 2.60 GHZ16 GB solderedIntegrated Intel Iris XE
OS
Windows 11 Pro + Win11 Canary VM.
Computer type
Laptop
Manufacturer/Model
ASUS Zenbook 14
CPU
I9 13th gen i9-13900H 2.60 GHZ
Motherboard
Yep, Laptop has one.
Memory
16 GB soldered
Graphics Card(s)
Integrated Intel Iris XE
Sound Card
Realtek built in
Monitor(s) Displays
laptop OLED screen
Screen Resolution
2880x1800 touchscreen
Hard Drives
1 TB NVME SSD (only weakness is only one slot)
PSU
Internal + 65W thunderbolt USB4 charger
Case
Yep, got one
Cooling
Stella Artois (UK pint cans - 568 ml) - extra cost.
Keyboard
Built in UK keybd
Mouse
Bluetooth , wireless dongled, wired
Internet Speed
900 mbs (ethernet), wifi 6 typical 350-450 mb/s both up and down
Browser
Edge
Antivirus
Defender
Other Info
TPM 2.0, 2xUSB4 thunderbolt, 1xUsb3 (usb a), 1xUsb-c, hdmi out, 3.5 mm audio out/in combo, ASUS backlit trackpad (inc. switchable number pad)

Macrium Reflect Home V8
Office 365 Family (6 users each 1TB onedrive space)
Hyper-V (a vm runs almost as fast as my older laptop)
Can I ask what you mean by the old and new installers? I don't have the Windows old folder. I clean installed 25H2 onto a wiped drive, and although I did burn the usb with Rufus, I went through the full oobe, setting up with internet and a microsoft account, but opted to set up as a new computer.

So are you saying that if it's burned with Rufus it uses the old installer? Is the new installer part of the usb if burned with the media creation tool then?
 

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    Windows 11 Home 25H2Core i5-1035G132gb
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    Windows 11 Home 25H2
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    Manufacturer/Model
    HP Pavilion 14-ce3606sa
    CPU
    Core i5-1035G1
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    32gb
    Hard Drives
    Samsung 870 evo sata ssd
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    Originally came installed with a 500gb H10 Optane ssd
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    Windows 11 HomeIntel Core i5-1035G116gb
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    Windows 11 Home
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    Manufacturer/Model
    HP Pavilion ce3606sa
    CPU
    Intel Core i5-1035G1
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    16gb
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    Hynix Gold P31 2TB
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    200mbps Starlink
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    Defender

My Computer My Computer

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Windows 11 Pro 25H212th Gen Core i7-1260P64 GB Micron PC4-25600Intel Iris Xe Graphics
OS
Windows 11 Pro 25H2
Computer type
PC/Desktop
Manufacturer/Model
Intel NUC12WSHi7
CPU
12th Gen Core i7-1260P
Motherboard
NUC12WSBi7
Memory
64 GB Micron PC4-25600
Graphics Card(s)
Intel Iris Xe Graphics
Sound Card
on-board Realtek HD Audio
Monitor(s) Displays
Dell U3219Q
Screen Resolution
3840 x 2160
Hard Drives
Samsung SSD 990 PRO 1TB
Crucial MX500 2 TB
Antivirus
Microsoft Defender
Ah that's it - I clicked "previous version of set up" when I installed. So that's the old installer then?
 

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    Windows 11 Home 25H2Core i5-1035G132gb
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    Windows 11 Home 25H2
    Computer type
    Laptop
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    HP Pavilion 14-ce3606sa
    CPU
    Core i5-1035G1
    Memory
    32gb
    Hard Drives
    Samsung 870 evo sata ssd
    Cooling
    Could be better
    Internet Speed
    50 mbps Starlink
    Browser
    Firefox
    Other Info
    Originally came installed with a 500gb H10 Optane ssd
  • At a glance

    Windows 11 HomeIntel Core i5-1035G116gb
    Operating System
    Windows 11 Home
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion ce3606sa
    CPU
    Intel Core i5-1035G1
    Memory
    16gb
    Hard Drives
    Hynix Gold P31 2TB
    Internet Speed
    200mbps Starlink
    Browser
    Firefox
    Antivirus
    Defender
Yep.
 

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Windows 11 Pro 25H212th Gen Core i7-1260P64 GB Micron PC4-25600Intel Iris Xe Graphics
OS
Windows 11 Pro 25H2
Computer type
PC/Desktop
Manufacturer/Model
Intel NUC12WSHi7
CPU
12th Gen Core i7-1260P
Motherboard
NUC12WSBi7
Memory
64 GB Micron PC4-25600
Graphics Card(s)
Intel Iris Xe Graphics
Sound Card
on-board Realtek HD Audio
Monitor(s) Displays
Dell U3219Q
Screen Resolution
3840 x 2160
Hard Drives
Samsung SSD 990 PRO 1TB
Crucial MX500 2 TB
Antivirus
Microsoft Defender
I wonder when that option will get removed ............. I always use the old installer.
 

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    Windows 11 Home 25H2Core i5-1035G132gb
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    Windows 11 Home 25H2
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    HP Pavilion 14-ce3606sa
    CPU
    Core i5-1035G1
    Memory
    32gb
    Hard Drives
    Samsung 870 evo sata ssd
    Cooling
    Could be better
    Internet Speed
    50 mbps Starlink
    Browser
    Firefox
    Other Info
    Originally came installed with a 500gb H10 Optane ssd
  • At a glance

    Windows 11 HomeIntel Core i5-1035G116gb
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    Windows 11 Home
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion ce3606sa
    CPU
    Intel Core i5-1035G1
    Memory
    16gb
    Hard Drives
    Hynix Gold P31 2TB
    Internet Speed
    200mbps Starlink
    Browser
    Firefox
    Antivirus
    Defender
So what's different using the new installer? I've never used it. Is there still the "custom" option and can you still delete and format drives/partitions in the new one?
 

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    Windows 11 Home 25H2Core i5-1035G132gb
    OS
    Windows 11 Home 25H2
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion 14-ce3606sa
    CPU
    Core i5-1035G1
    Memory
    32gb
    Hard Drives
    Samsung 870 evo sata ssd
    Cooling
    Could be better
    Internet Speed
    50 mbps Starlink
    Browser
    Firefox
    Other Info
    Originally came installed with a 500gb H10 Optane ssd
  • At a glance

    Windows 11 HomeIntel Core i5-1035G116gb
    Operating System
    Windows 11 Home
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion ce3606sa
    CPU
    Intel Core i5-1035G1
    Memory
    16gb
    Hard Drives
    Hynix Gold P31 2TB
    Internet Speed
    200mbps Starlink
    Browser
    Firefox
    Antivirus
    Defender
So what's different using the new installer? I've never used it.
That's the magic question that MS refuses to answer. They've never fully acknowledged this switch, and we're a year later after 24H2's release.

Why does it want to run as an "upgrade" install? Did they do this for security reasons?
Will legacy Setup disappear one day?
Why isn't it 100% compatible with certain unattended files that worked before 24H2?
 

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Windows 7
OS
Windows 7
Thanks - yes just seen there's another thread about it here

 

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    Windows 11 Home 25H2Core i5-1035G132gb
    OS
    Windows 11 Home 25H2
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion 14-ce3606sa
    CPU
    Core i5-1035G1
    Memory
    32gb
    Hard Drives
    Samsung 870 evo sata ssd
    Cooling
    Could be better
    Internet Speed
    50 mbps Starlink
    Browser
    Firefox
    Other Info
    Originally came installed with a 500gb H10 Optane ssd
  • At a glance

    Windows 11 HomeIntel Core i5-1035G116gb
    Operating System
    Windows 11 Home
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion ce3606sa
    CPU
    Intel Core i5-1035G1
    Memory
    16gb
    Hard Drives
    Hynix Gold P31 2TB
    Internet Speed
    200mbps Starlink
    Browser
    Firefox
    Antivirus
    Defender
I did a Windows 11 25H2 cleaninstall on my second computer on a compleet new unformatted drive, now I see an empty windows.old dir. do this have a funktion ?
Did you get all that @Cameraman1955 ? Assume you installed with the new installer as pictured above?
 

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    Windows 11 Home 25H2Core i5-1035G132gb
    OS
    Windows 11 Home 25H2
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion 14-ce3606sa
    CPU
    Core i5-1035G1
    Memory
    32gb
    Hard Drives
    Samsung 870 evo sata ssd
    Cooling
    Could be better
    Internet Speed
    50 mbps Starlink
    Browser
    Firefox
    Other Info
    Originally came installed with a 500gb H10 Optane ssd
  • At a glance

    Windows 11 HomeIntel Core i5-1035G116gb
    Operating System
    Windows 11 Home
    Computer type
    Laptop
    Manufacturer/Model
    HP Pavilion ce3606sa
    CPU
    Intel Core i5-1035G1
    Memory
    16gb
    Hard Drives
    Hynix Gold P31 2TB
    Internet Speed
    200mbps Starlink
    Browser
    Firefox
    Antivirus
    Defender
Thank you all for the nice comments, I shall explane what I did , I made my usbstick original with the mediacreationtool from the Microsoft site and install it on a brand new computer, on one disk (unformatted ssd). I install it with the new installer and I choose "Install as a new computer" so no backup.
 

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Windows 11 Pro 25H2 26200.7019Intel Core i7-8700KCorsair 32GB 4x DDR4-2998 / PC4-23900 DDR4 SD...AMD RX570
OS
Windows 11 Pro 25H2 26200.7019
Computer type
PC/Desktop
Manufacturer/Model
Self built midi tower
CPU
Intel Core i7-8700K
Motherboard
Gigabyte Z390GX
Memory
Corsair 32GB 4x DDR4-2998 / PC4-23900 DDR4 SDRAM UDIMM
Graphics Card(s)
AMD RX570
Sound Card
Sound Blaster Z
Monitor(s) Displays
2x IIyama Prolite X2380HS
Screen Resolution
1920x1080
Hard Drives
Samsung SSD 970 EVO Plus NVMe 1TB
Samsung SSD 970 EVO Plus NVMe 500GB
PSU
Seasonic 550W
Cooling
Noctua fans
Keyboard
Logitech G213
Mouse
Logitech Marble Mouse
Browser
Chrome
Antivirus
Norton
Other Info
Video/Audio editting machine
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