Memory Bandwidth Test
This test moves data through a large block of memory in your browser and reports how fast it goes. It also times random access, which shows how quickly the memory answers a request. Nothing is installed or uploaded.
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About this tool
What it measures
- Sequential copy, read and write in gigabytes per second, as the median of five passes.
- Random-access latency in nanoseconds, by following a shuffled chain of pointers through a large block, compared with the same test in a small block that fits in cache.
- Logical threads and the browser’s memory hint, where your browser reports them.
What it cannot do
This is a speed test written in JavaScript, not a RAM fault finder. It does not check every memory cell and it cannot spot unstable overclocks or failing modules. If you suspect faulty memory, boot a dedicated tester such as MemTest86 or Windows Memory Diagnostic and let it run for several passes.
Results are also lower than native tools report, because the browser sits between the test and the hardware. Use them to compare runs on the same device.
How to read the results
Results are gigabytes per second for copy, read and write, plus access latency. Compare runs on the same device: a number far below an earlier run points to background load or a power-saving mode. Absolute numbers are lower than native tools because JavaScript and the browser sit between the test and the hardware.
How to get steady numbers
- Close other tabs and heavy apps.
- Keep this tab in the foreground until the test ends.
- Run it two or three times and compare the medians.
The test size is chosen from your device’s memory hint, between 16 and 128 MB per buffer, and falls back to smaller buffers if the browser refuses the allocation.
Frequently asked questions
Why is the device memory value rounded?
Browsers report it as a power of two and cap it, usually at 8 GB, to reduce tracking. It is a hint, not your exact amount of RAM.
Can this find bad RAM?
No. Use a dedicated memory tester that runs outside the operating system for that.
Why is my result lower than other tools show?
JavaScript adds checks and runs inside the browser sandbox, so absolute numbers are lower. The test is useful for comparing before and after a change on the same device.
Can this find faulty RAM?
No. It is a speed test, not an error test. Use MemTest86 or Windows Memory Diagnostic for fault finding.
Why is my result lower than the speed printed on my RAM?
Browsers add overhead, and real programs rarely reach the theoretical peak. Compare your own results over time instead.
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