Exam Tip Flashcards
Antistatic tools
Static electricity, and therefore the risk of ESD, is much more prevalent in dry, cool environments.
Antistatic tools
Always put components in an antistatic bag, not on the bag.
Tip
Always disconnect power before repairing a personal computing device.
Tip
The CompTia A+ certification exams assume that all techs should back up systems every time before working on them, even though that’s not how it works in the real world.
Tip
CompTia only uses the term CPU, not microprocessor. Expect to see CPU on the 1101 exam.
Cache
Typically, the CompTIA A+ exams expect you to know that L1 cache will be the smallest and fastest cache; L2 will be bigger and slower than L1; and L3 will be the biggest and slowest cache. (This is not completely true anymore, with L1 and L2 running the same speed in many CPUs, but it is how it will appear on the exams.)
Cooling
A heat sink by itself (no fans) on a chip provides passive cooling. A heat sink and fan combination provides active cooling. You’ll sometimes hear the latter described as an active heat sink.
Catastrophic Failure
You’ll know when a catastrophic error occurs. The PC will suddenly get a blue screen of death (BSoD), what’s technically called a Windows Stop error.
Dual inline memory module (DIMM)
Some manufactures, and CompTIA drop the hyphen: SODIMM. You might see the RAM package spelled as SO-DIMM, SODIMM, or even SoDimm.
RAM
The CompTIA 220-1101 exam loves to test you on pin counts with RAM! It will challenge your knowledge of the various RAM types including DDR4, DDR4, and DDR5. Make sure you know their individual characteristics and differences. DDR3 DIMMs have 240 pins, for example, and DDR3 SO-DIMMs have 204 pins.
Be sure you are familiar with with single, dual, triple, and quad channel memory architecture.
🧠 Single Channel Memory
Data Path: One 64-bit channel.
Performance: Lowest bandwidth.
Use Case: Budget systems or when only one stick of RAM is installed.
Example: 1x8GB RAM stick in a system.
💽 Dual Channel Memory
Data Path: Two 64-bit channels = 128-bit total.
Performance: ~2x the bandwidth of single channel (in ideal cases).
Use Case: Standard for most modern consumer desktops and laptops.
Example: 2x8GB RAM sticks installed in the correct dual-channel slots (usually color-coded).
💾 Triple Channel Memory (rare)
Data Path: Three 64-bit channels = 192-bit total.
Performance: ~3x single channel.
Use Case: Some older Intel platforms (like X58 chipset) supported it.
Example: 3x4GB sticks on a triple-channel capable board.
🧮 Quad Channel Memory
Data Path: Four 64-bit channels = 256-bit total.
Performance: Up to 4x single channel bandwidth.
Use Case: High-end desktops (HEDT) and workstations (e.g., Intel X299, AMD Threadripper).
Example: 4x8GB or 8x8GB modules for maximum bandwidth.
DIMM vs. SO-DIMM
💻 DIMM (Dual Inline Memory Module)
Used In: Desktops, workstations, servers.
Size: Larger — about 133mm (5.25 inches) long.
Pins:
DDR3: 240 pins
DDR4: 288 pins
DDR5: 288 pins (with a different notch position)
Performance: Can support more memory chips, often better cooling and higher performance due to space and power availability.
🧳 SO-DIMM (Small Outline DIMM)
Used In: Laptops, mini-PCs, some all-in-ones, and small-form-factor systems like Intel NUCs.
Size: Smaller — about 67mm (2.66 inches) long.
Pins:
DDR3: 204 pins
DDR4: 260 pins
DDR5: 262 pins
Performance: Slightly less powerful than full-sized DIMMs, but very efficient for compact systems.
🆚 Key Differences:
Feature DIMM SO-DIMM
Size Larger (desktop-sized) Smaller (laptop-sized)
Typical Usage Desktops, servers Laptops, small PCs
Pin Count 240–288 (DDR3–DDR5) 204–262 (DDR3–DDR5)
Performance Higher (more thermal headroom) Slightly lower (space-constrained)
Upgrade Ease Easier to access and replace More cramped in laptops
So basically: DIMM = desktops, SO-DIMM = laptops. Want help figuring out what your system uses, or how to upgrade?
