Why a Memory Card That Looks Fine Can Ruin Your Shoot
- scarlettkim7
- Jan 26
- 3 min read
Updated: Jan 27
OFFLOADER Memory Card Check (Card Health Diagnose)
Memory cards manufactured since the early 2010s have benefited greatly from advances in NAND flash technology. Modern cards actively employ techniques such as over-provisioning, aggressive Flash Translation Layers (FTL), garbage collection, and Error Correction Codes (ECC), enabling the high read/write performance required for 4K video recording.
These technologies allow memory cards to:
Automatically replace problematic areas
Hide regions likely to fail
Recover data through ECC algorithms
making issues invisible at the surface level and extending usable lifespan.
However, this also means that a memory card can appear healthy while still being close to failure.
During recording, such hidden conditions may cause sudden slowdowns, dropped frames, or recording interruptions. From a creator’s perspective, identifying these risks before shooting is essential.
Limitations of Traditional Bad-Sector Checks
In the past, tools such as GM HDD Scan2 were commonly used to detect bad sectors and determine whether storage media could be safely reused.
With modern memory cards, however:
Damaged cells are often recovered through ECC,
Suspicious pages may be silently hidden by the controller
which means that simple read success/failure checks no longer provide meaningful insight until the card is already near total failure.
As a result, traditional bad-sector scanning methods are largely ineffective for evaluating the real condition of modern flash-based memory cards.
OFFLOADER’s Approach to Card Health Checking
OFFLOADER’s Card Health Diagnose function was designed specifically to address these limitations.
Rather than relying on a binary “readable or unreadable” test, OFFLOADER measures and visualizes response time degradation across the entire memory card. This approach allows users to assess whether a card is likely to cause performance issues during actual recording.
In addition, OFFLOADER evaluates whether the card’s internal structure has become fragmented, which can also negatively affect sustained performance.
Below is an example of a card check result displayed by OFFLOADER.
Understanding the Card Health Graph
The X-axis represents the position across the memory card, from the beginning to the end.
The Y-axis represents response time degradation during card access.
Higher values indicate slower-than-normal responses.
A green baseline at the bottom of the graph represents the normal response time reference.
Green regions
Represents response times ranging from normal up to 6× the normal response time. These areas are considered stable and suitable for use.
Yellow dots
Indicate response times greater than 6× the normal response time.
These areas may cause unstable performance or reduced reliability under sustained recording.
Red dots
Indicate response times greater than 16× the normal response time.
These regions suggest severe degradation and a high risk of operational failure.
How to Interpret the Results
Modern memory cards use over-provisioning to maintain performance by internally reserving spare capacity. When problematic areas are detected, they are automatically replaced, allowing the card to continue operating normally.
For this reason, the presence of some degraded regions does not necessarily mean the card must be discarded immediately.
However, if OFFLOADER identifies a card as having fragmented sectors or slow sectors, continued use without proper preparation may lead to slow write responses and recording interruptions during shooting.
In such cases, OFFLOADER recommends performing a media reset using a camera that supports this function.
Unlike a standard computer format—which typically updates only a small portion of the filesystem—a proper media reset initializes the entire card, producing an effect similar to TRIM. Some high-end cameras, such as the Sony Z90, support this type of initialization.
When performed correctly, OFFLOADER may confirm that a previously degraded card has returned to a usable state after the reset.
OFFLOADER’s Final Evaluation Categories
After analyzing response time degradation across the entire memory card, OFFLOADER provides a clear recommendation:
Usable
No immediate issues detected.
→ The card can be formatted in OFFLOADER and reused safely.
Media Reset Required
Fragmentation or response time degradation exceeds recommended thresholds.
→ Perform a proper media reset using a supported camera before reuse.
Not Recommended for Use
Severe response time degradation indicates a high probability of near-term failure.
→ Discontinuing use is recommended to prevent on-set recording issues.
In the last case, while discarding a card may feel wasteful, it is often the most cost-effective way to prevent far greater losses caused by interrupted or corrupted recordings.
This concludes an overview of OFFLOADER’s memory card check feature.In the next article, we will explore real-world scenarios where memory card issues cause recording interruptions, and how these problems can be avoided in professional workflows.
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