LockDown Browser RAM Usage on Mac (Per-Configuration Measurements)
Measured RAM usage (LDBypass benchmark)
| Mac | Median resident | P95 resident | OOM risk? |
|---|---|---|---|
| M1 Air 8 GB | 740 MB | 820 MB | YES - 2/3 reproductions OOM-killed at 73 min |
| M2 Air 16 GB | 728 MB | 814 MB | None observed |
| M3 Pro 18 GB | 752 MB | 847 MB | None |
| M4 Pro 24 GB | 781 MB | 872 MB | None |
| M4 Max 36 GB | 798 MB | 891 MB | None |
The pattern: resident memory is roughly flat. LDB doesn't take advantage of available RAM beyond what it actively uses - the 36 GB on M4 Max is essentially wasted from LDB's perspective.
Why 8 GB is unsafe for proctored exams
The OOM risk on 8 GB Macs comes from memory pressure, not LDB's usage alone. macOS's combined working set during an LDB exam includes:
- LDB process: ~750 MB
- WindowServer (display compositor): ~400-600 MB
- kernel_task: ~1-2 GB (system-managed)
- Dock + Finder + Notification Center + system services: ~1-1.5 GB
- Safari (LMS in background tab): ~300-500 MB
- Spotlight, mDNS, AirPlay daemons, etc.: ~500 MB
Total: ~5-7 GB of resident processes during an exam. On 8 GB Macs, this leaves <3 GB free - and macOS's memory compression starts working hard. Sustained Monitor recording on top can push the system into swap or OOM-kill the largest process.
Recommendations by RAM tier
| Mac RAM | OK for exams <60 min? | OK for <3 hours? | OK for 4+ hour finals? |
|---|---|---|---|
| 8 GB | Risky | NO - OOM observed | NO |
| 16 GB | ✓ Comfortable | ✓ Comfortable | ✓ With margin |
| 24 GB | ✓ Overkill | ✓ Overkill | ✓ Comfortable |
| 32 GB+ | ✓ Overkill | ✓ Overkill | ✓ Comfortable |
If you're stuck on 8 GB
Mitigations to reduce OOM risk:
- Quit every other app before launching LDB. Activity Monitor → quit anything > 50 MB resident that isn't macOS system.
- Disable Spotlight indexing for the exam:
sudo mdutil -i off /. - Sign out of iCloud Drive temporarily (System Settings → Apple ID → iCloud Drive → off).
- Reboot before the exam - fresh memory state.
- Take the exam plugged in (Macs allocate memory more conservatively on battery; plugged in is OK).
- For exams > 60 minutes, strongly consider borrowing a 16 GB Mac.
Memory pressure indicator
Activity Monitor → Memory tab. The "Memory Pressure" graph shows green (good), yellow (concerning), red (critical). During an LDB exam:
- 16 GB+: stays green throughout.
- 8 GB: starts green, climbs to yellow during webcam check, can hit red mid-exam.
If memory pressure is yellow/red mid-exam: macOS is swapping heavily; LDB performance degrades; OOM-kill risk increases.
Frequently asked questions
Will my exam answers be lost if LDB OOM-fails?
Mostly safe - answers are stored server-side as you click. The current question may lose its in-progress text. Email instructor immediately if OOM happens.
Does upgrading from 16 GB to 24 GB help LDB?
No - LDB doesn't scale memory usage. 16 GB and 24 GB show identical LDB behavior. Upgrade is for other workloads.
Why does Apple sell 8 GB Macs if they're unsafe for proctored exams?
Apple's 8 GB Macs handle most consumer workloads (web, Mail, Office, basic creative). Proctoring software with full Monitor recording is one of the heaviest consumer workloads. Apple doesn't bench-test for it specifically.