easyMultiple Choice
220-1201 Practice Question: A small office manager wants to upgrade the RAM…
A small office manager wants to upgrade the RAM in several identical workstations from 8 GB to 16 GB. The current modules are DDR3-1600. The company has a box of unused DDR3-1333 modules from an older system. Can they use these modules to upgrade the workstations?
⚠ Common exam trap
220-1201 often tests whether candidates know that mixed-speed RAM works but downclocks, confusing 'incompatible' with 'slower'.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Yes, they can add the DDR3-1333 modules, but all RAM will run at 1333 MHz.
DDR3 modules of different speeds are electrically compatible as long as they are the same DDR generation (DDR3) and fit the same slot. When mixed, the memory subsystem runs at the speed of the slowest module — here 1333 MHz — so the workstations will work but at reduced bandwidth. The manager can add the DDR3-1333 modules alongside the existing DDR3-1600 modules.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
No, because the speeds are different and will cause system instability.
Why it's wrong here
This statement is incorrect because different speeds of RAM within the same DDR generation, such as DDR3-1333 and DDR3-1600, are generally compatible. The system's memory controller will automatically detect the slowest module and configure all installed RAM to operate at that lower speed. This ensures system stability rather than causing instability, though it means the faster module will not perform at its maximum rated speed.
- ✗
Yes, but only if they replace the existing modules entirely with the DDR3-1333 modules.
Why it's wrong here
It suggests that replacing existing modules entirely is the *only* way to add the DDR3-1333 modules. In reality, DDR3 modules of different speeds can often be mixed. While replacing them entirely would work, it's not the sole solution and would unnecessarily discard the existing faster RAM, potentially limiting total memory capacity or performance if the existing modules were faster.
- ✗
No, because DDR3-1333 is not compatible with DDR3-1600 slots.
Why it's wrong here
This statement is incorrect because all DDR3 RAM modules, regardless of their specific speed rating (e.g., DDR3-1333 or DDR3-1600), use the same physical 240-pin DIMM slot type. The slot compatibility is determined by the DDR generation (DDR3 in this case), not the clock speed. Therefore, a DDR3-1333 module will physically fit into any motherboard designed for DDR3 RAM.
- ✓
Yes, they can add the DDR3-1333 modules, but all RAM will run at 1333 MHz.
Why this is correct
Modern memory controllers are designed to accommodate RAM modules with different clock speeds within the same DDR generation. When modules of varying speeds are installed, the memory controller will default to the speed of the slowest module to ensure synchronous operation and system stability. Consequently, all RAM, including the existing DDR3-1600, will operate at 1333 MHz.
Go deeper
Related to this question
Learn chapter
RAM Types and Memory Slots
Key term
CAN
A CAN (Controller Area Network) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer.
Key term
Bandwidth
Bandwidth is the maximum amount of data that can travel over a network connection in a given amount of time, usually measured in bits per second.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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