Here is a good article explaining Core Isolation and other Windows security measures:I turned off Core Isolation. Right now I don't see much difference, but I'll keep using it without it on for a while and see if it makes a big difference.
What could happen to my PC if it's off? I hate leaving it less secure and if I see little or no difference, I'll slide her back on.
Device protection in Windows Security
Learn how to access Windows 10 device security settings in Windows Security to help protect your device from malicious software.

BTW, sorry to hear that you have received flack for running Win 11 on technically unsupported hardware. I usually like to point out to people to do so with caution, basically just go in with your eyes open and realize that someday there may be difficulties with future updates that we cannot predict. However, I would venture to say that most of us here are enthusiasts who don't always color within the lines

Don't let some negative feedback discourage you. Ignore the non-believers!
In my case, for example, I have Windows 11 installed on about a dozen machines, and I think that only about two of them are technically within supported specs. A couple of my machines are at least 10 years old

My Computers
System One System Two
-
- OS
- Win11 Pro 24H2
- Computer type
- PC/Desktop
- Manufacturer/Model
- Self-built
- CPU
- Intel i7 11700K
- Motherboard
- ASUS Prime Z590-A MB
- Memory
- 64GB (Waiting for warranty replacement of another 64GB for 128GB total)
- Graphics Card(s)
- No GPU - Built-in Intel Graphics
- Sound Card
- Integrated
- Monitor(s) Displays
- HP Envy 32
- Screen Resolution
- 2560 x 1440
- Hard Drives
- 1 x 1TB NVMe SSD
1 x 2TB NVMe SSD
1 x 4TB NVMe SSD
3 x 512GB 2.5" SSD
1 x 4TB 2.5" SSD
5 x 8TB Seagate Barracuda HDD
- PSU
- Corsair HX850i
- Case
- Corsair iCUE RGB 5000X mid tower case
- Cooling
- Noctua NF-S12A chromax.black.swap case fans (Qty. 7) & Home Computer Specifications, Configuration, and Usage Notes General Specifications ASUS Prime Z590-A motherboard, serial number M1M0KC222467ARP Intel Core i7-11700K CPU (11th Gen Rocket Lake / LGA 1200 Socket) 128GB Crucial Ballistix RGB DDR4 3200 MHz DRAM (4 x 32GB) Corsair iCUE RGB 5000X mid tower case Noctua NH-D15 chromax.black CPU cooler Noctua NF-S12A chromax.black.swap case fans (Qty. 7) & Corsair LL-120 RGB Fans (Qty. 3)
- Keyboard
- Corsair K70 Max RGB Magnetic Keyboard
- Mouse
- Logitech MX Master 3
- Internet Speed
- 1Gb Up / 1 Gb Down
- Browser
- Edge
- Antivirus
- Windows Defender
- Other Info
- The five 8TB drives and three 512GB SSDs are part of a DrivePool using StableBit DrivePool software. The three SSDs are devoted purely to caching for the 8TB drives. All of the important data is stored in triplicate so that I can withstand simultaneous failure of 2 disks.
Networking: 2.5Gbps Ethernet and WiFi 6e
-
- Operating System
- Win11 Pro 23H2
- 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
- Mouse
- Buttonless Glass Precision Touchpad
- Keyboard
- Backlit, spill resistant keyboard
- Internet Speed
- 1Gb Up / 1Gb Down
- Browser
- Edge
- Antivirus
- Windows Defender
- Other Info
- WiFi 6e / Bluetooth 5.1 / Facial Recognition / Fingerprint Sensor / ToF (Time of Flight) Human Presence Sensor