Data transfer speed question

hj2k_x

hj2k_x

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Transferring data from one SATA harddrive to another on the same PC, on windows 7. First, I copy 50GB of stuff over at speeds of 45-60MB/sec(starting at 80MB/sec and then settling around 50MB/sec) and then then next lot, also 50GB, does not get over 36MB/sec.

What caused this drastic change in speed?

And does changing the jumper settings on the HDD itself from 1.5Gb/sec to 3.0Gb/sec make anything go any faster?

:)
 
What files are they? Big files transfer faster than small ones. WRT to the 1.5 GB jumper, I would say that it would not impact disk throughput, because I don't think your disk is moving data at anywhere near 1.5GB/sec to create a bottleneck in the first place. Remember that 320GB/sec is enough for 15k SCSI disks....
 
Conradl said:
What files are they? Big files transfer faster than small ones. WRT to the 1.5 GB jumper, I would say that it would not impact disk throughput, because I don't think your disk is moving data at anywhere near 1.5GB/sec to create a bottleneck in the first place. Remember that 320GB/sec is enough for 15k SCSI disks....
Click to expand...

We meet again :)

Indeed, the second 50GB batch contained many smaller files - I did not realise that made so much difference.

What kind of machines move data at 3GB/sec to warrant the jumper in the 1st place?
 
none really that you and i can afford.., it there for compatability with older sata controllers
 
The 1.5 versus 3gb is only the bus speed, and represents the fastest possible transfer rate. The problem with HDD is that it is easier to create a fast electronic bus than a fast physical disk to put data on the bus in the first place. The 1.5 is a just a different standard and the old drives could not reach that either....

Also remember that the new SAS drives are compatible with SATA, so they have made provision for that.
 
Not 3 GB/s it's Gigabit. The max speed of Sata1 is 150 MB/s and Sata 2 is 300 MB/s but that is only theory SSD get close to that speed that is why I'm not sure if this year or next we will see USB 3 and SATA 3.

Edit:

I have SATAII drives for personal use but I also use a RAID 0.
 
No, you can get SATAII drives :), but they don't work at 3GB/sec; nor does SATAI work at 1.5.... My point is that NO single HDD can transmit data off the physical platters fast enough to match the speed of the bus. That is why there is very little difference between IDE and SATA drivers, of the same make, in terms of throughput. An IDE133 drive will have the same effective transfer rate as SATAII, because the heads can only read and write the data at a given rate - which happens to be considerably slower than the bus rate.
 
Conradl said:
No, you can get SATAII drives :), but they don't work at 3GB/sec; nor does SATAI work at 1.5.... My point is that NO single HDD can transmit data off the physical platters fast enough to match the speed of the bus. That is why there is very little difference between IDE and SATA drivers, of the same make, in terms of throughput. An IDE133 drive will have the same effective transfer rate as SATAII, because the heads can only read and write the data at a given rate - which happens to be considerably slower than the bus rate.
Click to expand...
OK, I see what you are saying :)
 
Gixxa said:
Not 3 GB/s it's Gigabit. The max speed of Sata1 is 150 MB/s and Sata 2 is 300 MB/s but that is only theory SSD get close to that speed that is why I'm not sure if this year or next we will see USB 3 and SATA 3.

Edit:

I have SATAII drives for personal use but I also use a RAID 0.
Click to expand...

Good point, I always find myself guilty of mixing my Bs adn bs :)
 
So whats the average transfer rate on a SataII partitioned drive ie: copying from one partition to the other? I only get around 30 MB/s. Is this right?
 
If you do not have a RAID 30 MB/s is very good and normal.
 
30MB/s is good. As mentioned it depends on the size of the files that you copy. I once installed a new SAN (back when 750GB was a mind blowing amount of space!), and it took around 30 hours to transfer around 1 000 000 really small files from the old to the new device. Both devices had around 30 36GB SCSI disks, so it is relative to the type of IO....
 
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