Memory Test (RAM)

Test your RAM in the browser. Allocate memory, write and verify bit patterns, measure write and read speed, and count errors — no download or install needed.

The test asks the browser for a large block of memory. On devices with little free memory the tab may slow down, and some browsers close a tab instead of refusing memory. Save your work in other tabs first, and pick a small size on phones.

Test size

Pick a test size and press start.

Check Your Memory Without Booting Into a Tester

Bad memory rarely announces itself. It shows up as a program that crashes once a week, a file that will not open anymore, or a blue screen with a different message every time. The usual advice is to boot into MemTest86 and wait hours, which is more commitment than a quick suspicion deserves. This test gives you a faster first step: it fills a large block of memory with known patterns, reads every value back twice, and measures how fast your machine moves data while doing it. A clean pass will not certify your modules, but repeated errors here are a clear signal that the long test is worth your time.

Why Use This Memory Test?

Write and Double Verify

Every value is written, read back, inverted, and read again, so a cell that fails in only one direction still gets caught.

Real Throughput Numbers

Write and verify speeds in MB/s update live, so you can compare devices, browsers, or the same laptop before and after an upgrade.

Runs in a Worker Thread

The heavy work happens in a Web Worker, so the page stays responsive and the stop button always works.

No Install, No Upload

Everything runs in your browser tab. Nothing is downloaded, nothing leaves your device, and closing the tab frees the memory instantly.

How this Memory Test (RAM) works

When you start the test, the page creates a Web Worker, a separate browser thread that does the heavy work without freezing the tab. The worker requests memory from the browser in 16 MB blocks until it reaches the size you selected. Each block is filled with a calculated number pattern, and the position of every value determines what that value should be. This step measures write speed, since the browser has to push the full pattern out to physical memory.

The worker then reads every block back and compares each value against the number that should be there. Any mismatch counts as an error. After the first check, it flips every bit in the pattern and verifies the memory again. Testing both states matters because a faulty memory cell can hold a 0 correctly but fail on a 1, or the other way around.

While this runs, the page shows the phase, the progress, and the live throughput in megabytes per second. When the test finishes, you get the write speed, the verify speed, and the error count.

The browser decides how much memory a single tab may claim, so the test checks the memory your browser can reach rather than every module in your machine. A clean result tells you that this region reads and writes correctly at speed. Repeated errors are a strong signal to run a bootable tester such as MemTest86. Everything stays on your device, and closing the tab releases the memory instantly.

How to use this Memory Test (RAM)

1

Pick a test size

Choose how much memory to test, from 256 MB up to 2 GB. Start small on phones and older machines.

2

Run the pattern test

Press start and watch the worker fill the memory with patterns while the write speed updates live.

3

Read the verdict

The verify pass checks every value twice. Review the speeds and the error count when the test finishes.

Frequently Asked Questions

Can a browser really test my RAM?
Partly. The browser gives the test a large block of real memory, and the test writes and verifies every byte of it. What it cannot do is reach memory owned by the operating system or other programs, so treat it as a quick check of a meaningful sample, not a full scan.
Is this a replacement for MemTest86 or the Windows Memory Diagnostic?
No. Bootable testers run before the operating system loads, reach almost all installed memory, and use many more patterns over hours. This test is the quick, no-install first step you run when a machine starts acting strange.
Is it safe to run this memory test?
Yes. The test uses ordinary JavaScript inside the browser sandbox, and the operating system keeps full control of memory. The realistic worst case is a slow tab, or the browser ending the tab when it runs out of memory to give.
Why did the test stop before reaching my selected size?
The browser refused to hand over more memory. Browsers cap how much one tab may claim, and other tabs and programs shrink what is left. Close what you can and run the test again, or accept the smaller tested amount.
What does an error mean?
An error means a value read back different from what was written moments earlier. Run the test again. If errors keep appearing, run a bootable tester, reseat the memory modules, and disable any memory overclock such as XMP to see whether it stabilizes.
I got zero errors. Is my RAM fine?
It passed a real write-and-verify cycle, which rules out gross faults in the tested region. It does not certify the modules, because faults can live in memory the browser never touched or appear only after long heat and load.
Why is the speed lower than my RAM’s rated bandwidth?
The test runs JavaScript on one thread and includes pattern calculation in the numbers, while rated bandwidth comes from ideal multi-channel transfers. Use the result to compare runs and devices, not to check the sticker on the box.
Why do write and verify speeds differ?
The write phase mostly pushes data out to memory, while the verify phases read values, compare them, and flip bits in between. Different mixes of reading and writing move at different speeds on every machine.
Does the test work on phones and tablets?
Yes, in any modern mobile browser. Phones allow a tab far less memory than desktops, so start with 256 MB. If the browser reloads the page during the test, the device simply ran out of free memory.
Which symptoms point to bad RAM in the first place?
Random freezes, blue screens with changing error messages, programs that crash without a pattern, and files that turn up corrupted are the classic signs. They can also come from storage or drivers, which is why a memory check is a useful first filter.
Does any of my data leave the device?
No. The test allocates empty memory, fills it with calculated numbers, and verifies them locally. Nothing is uploaded, nothing is stored, and closing the tab releases everything.

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