When your camera suddenly slows down, stops recording, or struggles to keep up during a fast burst of shots, it more often than not comes down to one thing: cache.

This is one of those techy topics that may sound niche, but it actually has a big impact on real-world camera performance, especially for professional photographers and videographers who burst high-res images or shoot high-bitrate video.

In this article, we’ll explain what cache is, how it works, and why it matters for your photography or videography workflow.

We’ll keep things simple and clear, so you walk away with a real understanding of how internal camera cash and external cache work together behind the scenes. This lets you fine-tune your setup for faster shooting, fewer slowdowns, and a more seamless experience. Let’s dive right in!

Understanding Camera Cache and Buffering

Every digital camera has to do a lot of work in a very short time, especially when bursting RAW photos or recording high-resolution video. That’s where cache and buffering come in.

What is Cache in a Camera?

In simple terms, cache refers to short-term memory built into your camera. It acts like a waiting area where the image or video data goes right after it’s captured before it’s saved to your memory card.

This cache is often called a buffer, and it’s what allows your camera to keep shooting quickly without slowing down after every photo.

How Do Camera Buffers Work?

When you take a photo—especially in burst mode or when shooting RAW files—your camera doesn’t write that data directly to your memory card right away. Instead, it sends the data to its internal buffer, which temporarily holds it.

While that buffer is storing images, the camera quietly works in the background to transfer those files to your memory card. If your buffer is large and fast, your shooting stays smooth. But if it fills up before the card can catch up, your camera may freeze or slow down until space clears.

Imagine pouring water into a funnel that drains into a bottle.

You can pour water (photos or video data) into the funnel very quickly, but the bottle (your memory card) can only accept it at a certain speed. The funnel itself is your camera’s cache or buffer—it temporarily holds the overflow.

If you pour too fast and the funnel fills up, water starts backing up, and you have to stop pouring until it drains. But if the funnel and the bottle’s neck are wide, the flow continues smoothly without interruption, and the faster you can pour.

Understanding External Cache

Now that we’ve covered the internal buffer—the short-term memory built into your camera—let’s talk about the external cache: the part that lives inside your memory card.

What Is External Cache?

External cache refers to the small, high-speed memory and data management systems built into certain fast memory cards. It helps the card handle large amounts of data more efficiently, especially when you’re bursting high-resolution photos or recording 4K, 6K, or even 8K video.

In simple terms: just like your camera has a buffer, some high-performance memory cards have their own internal helpers that make writing and managing data much faster and more stable.

These cards are like the bottles with wide necks in the funnel analogy above—they let data drain from the camera’s buffer faster, which helps prevent slowdowns and keeps your shooting flow uninterrupted.

Internal vs. External Cache: What’s the Difference?

• Internal Cache (Camera Buffer): Temporary memory inside your camera that holds images or video right after capture. It’s the first stop before anything is saved to your card.
• External Cache (in Memory Cards): Built-in features of advanced memory cards that help them receive, process, and store data faster and more reliably—kind of like having a smarter, more organized storage unit.

The two are designed to work together. The camera’s buffer keeps things moving while you shoot, holding data temporarily. The memory card’s external cache helps offload that data quickly—so the buffer doesn’t fill up, and your camera stays ready for the next shot.

When both are working efficiently, you get faster performance, fewer slowdowns, and a much better shooting experience—especially during intense or high-volume sessions.

How Cache Affects Camera Performance

Cache plays a behind-the-scenes role in how fast and smoothly your camera operates—especially when you’re pushing it hard.

• Buffering Speed: A fast internal cache lets you shoot longer bursts without your camera freezing up. The buffer catches the data so your camera doesn’t have to wait on the memory card.
• Lag and Processing Time: Cache also helps speed up tasks like autofocus, image previews, and saving files—so you’re not stuck waiting between shots.
• Low-Light and Long Exposures: High-res or long-exposure images take more time to process. A good cache helps handle that extra data without slowing you down.
• Video Recording Stability: Cache memory supports smooth video capture at higher resolutions and frame rates by preventing dropped frames and buffering delays.

Internal vs. External Memory: Pros and Cons

Internal Camera Cache

• Pros: Delivers very fast data handling directly within the camera, allowing for smooth burst shooting and responsive performance during high-speed or high-resolution captures.
• Cons: Limited in size—once it fills up, the camera slows down or pauses until the data is written to the memory card.

External Memory Cache

• Pros: Offers greater storage capacity and, with high-performance cards, can help offload data from the internal buffer more efficiently, supporting longer shooting sessions.
• Cons: Performance depends on card speed and compatibility—slower cards can become a bottleneck, causing lag and interrupting shooting flow.

Optimizing Your Camera’s Cache Performance

While there are a few ways to manage your camera’s cache performance—like lowering resolution, reducing frame rate, or switching to more compressed file formats—these options usually come with compromises. You might gain speed, but you lose image quality, dynamic range, or editing flexibility. And no matter what settings you choose, there’s one thing you can’t change: your camera’s built-in buffer. You can’t expand it or upgrade it.

What you can do is reduce the pressure on that buffer by using a better external cache. In other words, a faster memory card. A high-performance card helps offload data more quickly, which means the internal cache clears quicker—and your camera can keep shooting without interruption.

However, not all memory cards are created equal, and not all speed markings on the cards tell the full story.

Choosing the Right Memory Card for Buffer-Heavy Shooting

When choosing a card for serious photo or video work, look for sustained write speed—not just peak numbers. Peak speeds are often marketing-driven and used by many questionable manufacturers to make their cards appear better than they are. In reality, these numbers often reflect short spurts under ideal conditions. What matters in real-world use, especially for high-resolution video or continuous bursts, is how fast the card can write data consistently.

This is where Video Speed Class ratings and Video Performance Guarantee ratings come in.

Video Speed Class is marked on a card with the letter “V,” followed by a number. The video Performance Guarantee rating is marked on a card with a number inside a little clapper icon. In both cases, the number indicates a minimum sustained write speed in megabytes per second. These ratings ensure a card won’t drop below a certain speed.

For example, SDXC memory cards carrying the  V30, V60, or V90 marking indicate the minimum sustained write speed of 30MB/s, 60MB/s, or 90MB/s, respectively. At the same time, CFexpress cards with the VPG200 or VPG400 rating ensure a write speed won’t drop below 200MB/s or 400MB/s, depending on the rating—critical for smooth, uninterrupted video capture.

At ProGrade Digital, we go beyond those baseline guarantees.

Since Video Speed Class ratings max out at 90MB/s and VPG ratings at 400MB/s, but our CFexpress memory cards are designed for professional workflows that demand far more than 90MB/s or 400MB/s, we clearly display sustained write speed right on the label of our latest cards, marked as “Sus. W” followed by the exact speed in MB/s. This gives you a true, transparent measure of real-world performance—so you know your card can keep up, even in the most demanding scenarios.

In short, you can tweak your camera settings to improve performance—but if you want to unlock your camera’s full potential without any compromise, upgrading to the right memory card is the way to go.

>>> Browse high-speed memory cards developed for professional photography and videography.

Conclusion

Great performance comes from knowing how your tools work—and how to make the most of them. Understanding cache and memory gives you more control, fewer slowdowns, and a smoother creative flow.

When your gear keeps up, your ideas can too. Happy shooting!