Computer Speeds & Units (Bits, Bytes, Hz, and Architectures)

Understanding how we measure data and speed is foundational: from bits & bytes to kilobytes through yottabytes, from CPU cycles (Hz) to how quickly the CPU reaches memory, and why 32-bit vs 64-bit still matters.

🔹 1️⃣ Bits, Bytes, and Memory Units

• Bit = the smallest unit (0 or 1).
• Byte = 8 bits.
• Binary-scaled units (base 2) commonly taught to beginners:
  • 1 KB = 1,024 bytes
  • 1 MB = 1,024 KB
  • 1 GB = 1,024 MB
  • 1 TB = 1,024 GB
• Even Larger : PB, EB, ZB, YB with real-world anchors (e.g., Facebook servers in PBs, global internet traffic in EBs, “whole data in the world” a few ZBs).

⚠️ Note for learners: Operating systems and storage vendors sometimes use decimal (10³) labels; this lesson uses the binary (2¹⁰=1,024) view shown in the slides. 

🔹 2️⃣ CPU Access to Memory: Why Levels Matter

The closer the storage is to the CPU, the faster the access:

• Registers (inside CPU): instantly available values for current instructions.
• Cache (on-chip): very fast access to recently used data/instructions.
• Main Memory (RAM): fast, but slower than cache.
• Secondary Storage (SSD/HDD): slowest among these tiers, used for long-term storage.
  Slides emphasize: “Instantly / semi-instantly available data… makes access to data much faster.”

🔹 3️⃣ CPU Speed & Hertz (Hz)

• Clock speed / frequency measures how many cycles per second the CPU performs, in Hertz (Hz).
• 3.2 GHz = 3.2 billion cycles per second.
• On each cycle, billions of transistors open/close (binary switching) to execute instructions.
• Transistor = binary switch that prevents or allows electricity (OFF/ON → 0/1). 

🔹 4️⃣ 32-bit vs 64-bit (x86 vs x64)

Address space & capacity

• 2³² = 4,294,967,296 bytes ≈ 4 GB addressable by a 32-bit system.
• 2⁶⁴ = 18,446,744,073,709,551,616 bytes ≈ 16 EB (vastly larger) for 64-bit.

Naming

• 32-bit: x86 / x86-32
• 64-bit: x64 / x86-64

Performance

• 64-bit can handle twice as many bits per cycle (within the same generation), enables larger data types and more RAM.

Compatibility (as shown in slides)

• 32-bit CPU → runs 32-bit OS & 32-bit software only.
• 64-bit CPU → can run 64-bit & 32-bit OS/software.
• If you install a 32-bit OS on a 64-bit CPU, you can run 32-bit software only (you won’t benefit from 64-bit apps or large RAM).

RAM reality

• 32-bit OS: can allocate only about 4 GB.
• 64-bit OS: can allocate much more (practically limited by hardware/edition).
  If you have ≥ 4 GB RAM, you should use 64-bit CPU + 64-bit OS to utilize it fully. 

🔹5️⃣ How to Know Your Device Specifications on Windows

📖 1️⃣ Basic Specifications (Processor, RAM, and System Type)

🧭 Method 1: Using “About This PC”

1️⃣ Press Windows + I → open Settings.
2️⃣ Go to System → About.
3️⃣ Under Device specifications, you’ll see:

• 💻 Processor: CPU model and speed (e.g., Intel Core i7-10750H @ 2.60 GHz).
• 🧠 Installed RAM: total physical memory (e.g., 16 GB).
• ⚙️ System type: whether your Windows and processor are 32-bit or 64-bit.
  → Example: “64-bit operating system, x64-based processor.”

📖 2️⃣ GPU & Graphics Card Details

🧭 Method 2: Using Device Manager

1️⃣ Press Windows + X → select Device Manager.
2️⃣ Expand Display Adapters.
3️⃣ You’ll see one or more GPUs listed:

• Integrated GPU (e.g., Intel UHD Graphics).
• Dedicated GPU (e.g., NVIDIA GeForce RTX 3060 or AMD Radeon RX 6600).

💡 Alternative (fastest)

Press Windows + R, type dxdiag, press Enter.

• Go to the Display tab → see GPU name, driver version, and VRAM (memory).

📖 3️⃣ Storage (SSD / HDD Type & Capacity)

🧭 Method 3: Using File Explorer

1️⃣ Open This PC.
2️⃣ Right-click any drive → Properties.
3️⃣ View:

• Used space / Free space / Total capacity.

⚙️ To know the physical drive type

Press Windows + S, type “Defragment and Optimize Drives” → open.

• Under Media type, you’ll see:
  • “Solid State Drive (SSD)” or
  • “Hard Disk Drive (HDD)”.

📖 4️⃣ Advanced Full System Information

🧭 Method 4: Using System Information Tool

1️⃣ Press Windows + R, type msinfo32, press Enter.
2️⃣ This opens the System Information window showing:

• OS version
• Manufacturer, model
• BIOS version
• Installed RAM
• Processor details
• System type (32/64-bit)
• Boot mode, etc.

📋 You can also Export this report:
File → Export → choose location.

📖 5️⃣ Using Command Prompt or PowerShell (for advanced users)

💻 Command Prompt:

Press Windows + R, type cmd, press Enter then use the following commands:

• CPU info → wmic cpu get name
• RAM info → wmic computersystem get totalphysicalmemory
• System type → wmic os get osarchitecture

⚡ PowerShell:

Run → Get-ComputerInfo | Select CsName, OsName, OsArchitecture, CsSystemType, CsTotalPhysicalMemory