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Performance cut in half on new drive

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Hi!

I recently installed two SATA 400GB seagates, one of them has dropped a lot in performance. Performance (mostly tested reading) is about half of what it used to be. If I perform an SFV-check on 1.5GB of data several times it might take 39s the first time, 30s the second time and 44s the third time, for exactly the same set of data there should be much less difference than 50% between runs. The same operation takes 37 sec on a much older 120GB drive.

When copying files (for example digital photos around 1MB each) it is clear that the drive can be very fast for a time and then halt (copying one image might take 3 seconds) just to start of in full speed again.

I've checked the cables and found no problems, I've also switched the drive to use the other SATA port (switched with the other drive that workes fine), but still the same problems. Is there any way to get more info about what's wrong with the drive?

Is the drive about to fail? Should I wipe it empty and return it? The drive is only a few months old, and has not done much else than extremely light file storage. The main problem is not that the performance is lower that's only annoying what makes me nervous is the inconsistency of the drive (I backup every change made now just to be safe).

Any suggestions? Ideas on what to do?

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Probably this is due to Windows memory caching. That's why you get irregular times during multiple times, because parts of the data is already in cache memory. What operating system are you using, I'm guessing it's Windows XP. Also, an important factor is how much system RAM you have?

The copying starts quickly because it is caching the data to RAM, i.e. the disk is only read until the buffer is filled. Then the system slows down when Windows starts to offload data from the cache memory, the disk then has to read and write simultaneously which slows down the copying. When the data is written and the buffer has room again, then the data is again only read to the buffer and the copying speeds up again only to slow down once again when writing to disk begins.

The speed depends on the amount of data you are copying. If you have for example 1GB of RAM and you are copying 100MB, then the copying would be very fast, because all of the data fits to the memory cache of Windows, which is then emptied by writing to the disk, also very quickly because reading the data has already ended.

Hope this was explained extensively enough.

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Probably this is due to Windows memory caching. That's why you get irregular times during multiple times, because parts of the data is already in cache memory. What operating system are you using, I'm guessing it's Windows XP. Also, an important factor is how much system RAM you have?

The copying starts quickly because it is caching the data to RAM, i.e. the disk is only read until the buffer is filled. Then the system slows down when Windows starts to offload data from the cache memory, the disk then has to read and write simultaneously which slows down the copying. When the data is written and the buffer has room again, then the data is again only read to the buffer and the copying speeds up again only to slow down once again when writing to disk begins.

The speed depends on the amount of data you are copying. If you have for example 1GB of RAM and you are copying 100MB, then the copying would be very fast, because all of the data fits to the memory cache of Windows, which is then emptied by writing to the disk, also very quickly because reading the data has already ended.

Hope this was explained extensively enough.

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When copying I copy the data to another drive, and 3 seconds to copy 1MB would be kind of slow anyway :). The timed tests are done just reading from the drive, it is resonable that the second run could be a little faster than the first run but the third run is 50% slower than the second run. I also doubt that WinXP Pro cache has anything to do with it, I've tested with up to 20GB of data and I don't think that caching makes a big difference when reading 20GB.

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