commands/hardware/hardware-profilers/by-component/profile-ram.md

You are performing an exhaustive RAM (memory) profile of the system.

Your Task

Generate a comprehensive memory analysis covering all aspects of RAM configuration, performance, and utilization.

1. Memory Module Inventory

• Number of modules: Total DIMMs installed
• Slots used/available: Occupied vs. total slots
• Module locations: Which slots contain modules
• Form factor: DIMM, SO-DIMM, etc.
• Module manufacturers: Per-module vendor
• Part numbers: Specific module part numbers
• Serial numbers: Per-module serial numbers

2. Memory Specifications

• Total capacity: System total in GB
• Per-module capacity: Size of each DIMM
• Memory type: DDR3, DDR4, DDR5, LPDDR, etc.
• Speed ratings: Configured speed and maximum speed
• Clock frequency: MT/s or MHz
• Voltage: Operating voltage (1.2V, 1.35V, 1.5V, etc.)
• Data width: 64-bit, 72-bit (ECC)
• Total width: Physical bus width

3. Memory Timings and Performance

• CAS latency: Primary timing (CL)
• RAS to CAS delay: tRCD
• Row precharge time: tRP
• Row active time: tRAS
• Command rate: 1T or 2T
• XMP/DOCP profiles: Available overclocking profiles
• Current vs. rated speed: Compare actual to maximum
• Memory bandwidth: Theoretical and actual

4. Memory Technology Features

• ECC support: Error-correcting code capability
• Channel configuration: Single, dual, triple, quad channel
• Rank configuration: Single rank, dual rank per module
• Memory controller: Integrated vs. discrete
• NUMA configuration: Non-uniform memory access (multi-CPU systems)
• Interleaving: Memory interleaving status

5. Current Memory Usage

• Total memory: Available to system
• Used memory: Currently allocated
• Free memory: Completely unused
• Available memory: Free + reclaimable
• Buffers: Kernel buffer cache
• Cached: Page cache
• Active/Inactive: Hot and cold memory
• Dirty memory: Modified pages not yet written
• Writeback: Currently being written back

6. Swap Configuration

• Swap total: Total swap space
• Swap used: Currently used swap
• Swap type: Partition, file, or zram
• Swappiness: Kernel swap tendency (0-100)
• Swap devices: List of swap locations
• Swap priority: If multiple swap devices

7. Memory Pressure and Performance

• Page faults: Major and minor fault rates
• Swap in/out rates: If swap is active
• Memory pressure: OOM events, thrashing indicators
• Huge pages: Transparent huge pages configuration
• NUMA statistics: Memory locality (if applicable)
• Memory errors: ECC errors if supported

8. Virtual Memory Configuration

• Virtual memory parameters: vm.swappiness, vm.vfs_cache_pressure
• Overcommit settings: Memory overcommit mode
• OOM killer settings: Out-of-memory behavior
• Huge page configuration: Transparent huge pages, huge page pool

Commands to Use

DMI/Hardware information:

• sudo dmidecode -t memory
• sudo dmidecode -t 16 - Physical memory array
• sudo dmidecode -t 17 - Memory device details

Memory status:

• free -h
• cat /proc/meminfo
• vmstat -s
• vmstat 1 5 - Memory statistics over time

Module details:

• sudo lshw -class memory
• sudo decode-dimms - Detailed DIMM info (if i2c-tools installed)

Performance and timings:

• sudo dmidecode -t memory | grep -i speed
• sudo dmidecode -t memory | grep -i timing
• cat /sys/devices/system/edac/mc/mc*/dimm*/dimm_label - DIMM labels

Memory bandwidth:

• sudo dmidecode -t memory | grep -i bandwidth
• Use sysbench memory for benchmarking (if installed)

Swap information:

• swapon --show
• cat /proc/swaps
• sysctl vm.swappiness

Virtual memory tuning:

• sysctl -a | grep vm.
• cat /proc/sys/vm/overcommit_memory

Memory errors (ECC systems):

• sudo edac-util -v (if available)
• sudo ras-mc-ctl --errors

NUMA information:

• numactl --hardware (if NUMA system)
• cat /proc/buddyinfo

Output Format

Executive Summary

Memory Configuration: [total] GB, [type] @ [speed] MT/s
Modules: [X] x [Y]GB ([channel] channel, [rank] rank)
Technology: [ECC/Non-ECC], [feature highlights]
Current Usage: [X]% ([used]/[total] GB)

Detailed Memory Profile

Module Inventory:

Slot 1 (DIMM_A1): [manufacturer] [part-number]
  - Capacity: [GB]
  - Type: [DDR4/DDR5]
  - Speed: [MT/s]
  - Voltage: [V]
  - Serial: [S/N]

Slot 2 (DIMM_A2): ...

Memory Configuration:

• Total Capacity: [X] GB
• Memory Type: [DDR4/DDR5]
• Channel Mode: [Dual/Quad] Channel
• Configured Speed: [MT/s] ([MHz])
• Maximum Supported Speed: [MT/s]
• Voltage: [V]
• ECC: [Enabled/Disabled/Not Supported]

Memory Timings:

• CAS Latency: [CL]
• tRCD: [ns]
• tRP: [ns]
• tRAS: [ns]
• Command Rate: [1T/2T]

Current Usage Statistics:

Total:        [X] GB
Used:         [Y] GB ([Z]%)
Free:         [A] GB
Available:    [B] GB
Buffers:      [C] MB
Cached:       [D] GB
Active:       [E] GB
Inactive:     [F] GB

Swap Configuration:

• Swap Total: [X] GB ([partition/file/zram])
• Swap Used: [Y] GB ([Z]%)
• Swappiness: [value]
• Devices: [list]

Performance Metrics:

• Page Faults: [rate] per second
• Swap Activity: [in/out rates]
• Memory Bandwidth: [theoretical GB/s]
• Huge Pages: [configured/available]

Virtual Memory Tuning:

• vm.swappiness: [value]
• vm.vfs_cache_pressure: [value]
• vm.overcommit_memory: [value]
• Transparent Huge Pages: [enabled/disabled]

Memory Assessment

Configuration Analysis:

• Channel utilization: [optimal/suboptimal]
• Speed optimization: [running at spec/underclocked]
• Capacity per channel: [balanced/unbalanced]
• Upgrade path: [recommendations]

Performance Considerations:

• Memory pressure: [low/medium/high]
• Swap usage: [analysis]
• Bottleneck assessment: [findings]

AI-Readable JSON

{
  "memory_modules": [
    {
      "slot": "",
      "manufacturer": "",
      "part_number": "",
      "serial_number": "",
      "capacity_gb": 0,
      "type": "DDR4|DDR5",
      "speed_mts": 0,
      "voltage": 0.0,
      "form_factor": "DIMM|SO-DIMM"
    }
  ],
  "configuration": {
    "total_capacity_gb": 0,
    "memory_type": "",
    "channel_mode": "single|dual|quad",
    "configured_speed_mts": 0,
    "max_speed_mts": 0,
    "ecc_enabled": false,
    "slots_used": 0,
    "slots_total": 0
  },
  "timings": {
    "cas_latency": 0,
    "trcd": 0,
    "trp": 0,
    "tras": 0
  },
  "usage": {
    "total_gb": 0.0,
    "used_gb": 0.0,
    "free_gb": 0.0,
    "available_gb": 0.0,
    "cached_gb": 0.0,
    "usage_percent": 0.0
  },
  "swap": {
    "total_gb": 0.0,
    "used_gb": 0.0,
    "type": "partition|file|zram",
    "swappiness": 0
  },
  "features": {
    "ecc_supported": false,
    "numa": false,
    "huge_pages_enabled": false
  }
}

Execution Guidelines

1. Use sudo liberally: Most detailed memory info requires root
2. Parse dmidecode carefully: Extract all per-DIMM details
3. Cross-reference data: Verify findings using multiple sources
4. Calculate derived values: Bandwidth, channel utilization, etc.
5. Check for errors: Look for memory error logs
6. Assess configuration: Identify optimization opportunities
7. Consider upgrade paths: Suggest meaningful improvements
8. Monitor dynamic metrics: Capture usage over brief period

Important Notes

• Some details require specific tools (i2c-tools for SPD data)
• ECC information only available on systems with ECC support
• Memory timings may not be fully exposed on all systems
• Virtual machines may not expose full memory details
• NUMA information only relevant for multi-CPU systems
• Benchmark tools (sysbench, memtester) can provide additional insights

Be extremely thorough - capture every detail about the memory subsystem.