Why NAND Flash Erase Speed Still Matters (And Why It’s Worth a Patent)

NAND flash feels instant, but it isn’t — and that gap is where the stutters come from.

Modern devices feel fast. Phones boot quickly. Files copy in seconds. Apps install while you’re barely paying attention. So it’s easy to assume that the memory underneath it all is operating at nanosecond speeds.

Here’s the quiet truth: NAND flash memory is fast compared to old hard drives, but slow compared to everything else in the system. And that mismatch is exactly why companies still spend time, money, and patent filings trying to shave milliseconds off storage behavior.

This article breaks down a recent NAND-related patent in plain English, explains why erase timing actually matters, and why a company like OPPO would bother protecting something that sounds so small on paper.

The basic NAND problem nobody talks about

NAND flash has a rule that makes engineers grumble: you can’t simply overwrite data. Before new data can be written, the memory has to be erased — and erase happens at the block level, not neatly at the file level.

That erase step is slow. Not “wait five minutes” slow, but slow enough that the rest of the system notices. When erase happens at the wrong time, everything pauses just long enough for humans to feel it.

This is where the trouble starts. If the system waits until the last moment to erase memory, writes stall. If it erases too aggressively, it wastes power and wears out the flash faster. Good storage behavior lives somewhere in the middle.

A quick reality check on timing

This is where a lot of intuition breaks down. CPU instructions happen in nanoseconds. RAM access is measured in tens of nanoseconds. NAND flash doesn’t live in that world.

Very roughly speaking, NAND read operations take tens of microseconds, writes take hundreds of microseconds to a millisecond, and erase operations usually take several milliseconds. That means an erase can be millions of times slower than what the CPU is doing at that moment.

Those milliseconds matter. They show up as a file copy that briefly drops to zero, an app install that “hangs” for a beat, or a phone that stutters during an update. You may never see the word “erase,” but you absolutely feel its timing.

The parking lot analogy

An easy way to think about NAND is a parking lot.

Writing data is like parking a car. Erasing a block is like bulldozing a whole section of the lot so new cars can park there. If you wait until cars are already lined up to start bulldozing, traffic backs up and everyone gets annoyed.

A smarter system bulldozes earlier, during quiet hours, so when cars arrive there are already clean, open spaces waiting. That’s the entire idea behind predictive erase and block switching.

It’s not flashy. It’s not magic. It’s preparation.

What this patent is really doing

The published patent application WO2025119173A1 focuses on managing NAND erase operations ahead of time instead of reacting at the last second.

The storage controller keeps track of how many erased blocks it has available and watches system behavior. When it sees pressure coming — or simply notices the pool getting low — it schedules erase work in the background.

Then, when real write requests arrive, the controller can immediately switch to a block that’s already erased instead of stopping everything to clean house first. Writes go through smoothly, and the user never sees the pause.

The clever part isn’t the erase itself. It’s when the erase happens and which blocks are chosen so the controller doesn’t create more work for itself later.

Why this isn’t “just garbage collection”

Traditional garbage collection tends to be reactive. Space gets tight, pressure builds, and the controller starts cleaning up because it has no choice.

This patent shifts that behavior into a predictive model. The controller prepares erased space before it becomes urgent, spreads erase work across quieter periods, and avoids doing heavy lifting during high-priority writes.

That difference sounds subtle, but in real devices it affects latency spikes, thermal behavior, battery draw, and long-term wear. Storage that feels smooth under stress almost always has better scheduling behind the scenes.

Is this really worth patenting?

In the NAND world, absolutely.

Most modern flash innovation isn’t about inventing new memory types. It’s about firmware behavior, controller logic, and tiny improvements that add up over billions of operations.

A few milliseconds avoided here and there may not sound dramatic, but across millions of phones and years of use, it becomes real product differentiation. It also becomes valuable intellectual property, especially in industries where cross-licensing is the norm.

Many patents like this exist as much for defense as for offense. If you don’t protect your implementation, someone else will, and suddenly you’re negotiating licenses for behavior you already use.

So who filed this — a lone inventor or a major player?

This patent wasn’t filed by one person with a clever idea scribbled on a napkin. It was filed by Guangdong OPPO Mobile Telecommunications Corp., Ltd., the company behind the global OPPO smartphone brand.

OPPO was founded in 2004 and has grown into one of the world’s largest smartphone manufacturers, competing directly with names like Samsung, Xiaomi, and Apple in many markets. They employ tens of thousands of people and invest heavily in research and development.

OPPO is also a prolific patent filer, with tens of thousands of patents spanning wireless communications, imaging, charging technology, and system-level firmware like storage controllers. This NAND patent fits squarely into that broader strategy.

In other words, this isn’t a novelty idea. It’s a small but deliberate improvement from a company that ships hardware at massive scale, where shaving milliseconds off storage behavior actually matters.

Put simply: erase timing isn’t glamorous, but when it’s wrong, everyone notices. And when it’s right, nobody ever thinks about it — which is exactly the point.