And let's assume those badly behaving, slow writing blocks are fairly evenly distributed across the card.ĬrystalDiskMark's is just doing some very basic sequential reads, sequential write, random read and random write tests in various different sizes. Let's say 5 times longer or 3.555 milliseconds. Let's say 0.1% of the blocks take abnormally longer. At 90MB/s it should take 711 microseconds to write a block. Let's say this card should write at 90MB/s. This particular card is using 64KB blocks. Are there any other utilities available that might detect both errors and the write speed dropping very low for certain blocks?Īs a professional software developer of 31 years I'm going to respectfully disagree. The camera detects the problem and probably beeps to indicate it, closes the current file and starts a new file.Īnyway I just wanted to share that just because h2testw reports a clean test doesn't mean that certain blocks did not take very long to write which will likely reek havoc with your dash cam. I'm sure when the dashcam runs into one of those blocks that takes like 2 seconds to write, ultimately what happens in the RAM buffer holding the frames not written to the card yet gets over written. I wish h2testw would track how many blocks wrote under a certain threshold speed. I was luckily I happened to be watching a noticed it. But it certainly cause a camera problems. And if 99.9% of the blocks wrote at full speed the 0.1% wrote very slow it wouldn't impact the average write speed for the entire test very much. An error didn't occur, it just took much longer than it should have for a write. I saw a number of times were a single write took very long, like 2 seconds. But luckily I was watching it very closely while it was testing. ![]() I forget the exact speed but let's just say it was 82.8 MB/s. The test passed and also reported a good write speed. I did not format it first because I wanted to test it in the same condition it was in since it was recently acting up. ![]() And there is a gap in time at the end of that short file and the start of the next file.įrom reading here I decided to run h2testw on the SD card. When I look at the files there are quite a few that don't contain the right amount of data / length of video. It would work for a while then act up again. I tried reformatting the card, resetting the camera, etc. The camera in my Wife's jeep has will randomly start beeping in odd patterns. The camera in my truck has been working perfectly. I bought two Samsung 256GB Evo Select SD cards. I installed a Viofo Pro Duo in my truck and my Wife's Jeep recently.
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