Hard disk speeds

I believe that the issue before had to do with whether or not the drives were on the same channel.  On separate channels, I believe that then, as with now, they will negotiate their own speeds.

Keep in mind this is just referring to the transfer speed.  Seek times and latency of two drives should be independent of each other.

thats depend upon data.. let's say you have connected 2 HDD's   1 sata and 1 SSD bothe IOPS is different.

if the SSD is the active partition having O/S and processing the data then the speed of processing is high ... at the same time it's saving data on its self .. then the IOPS performs excellently.

if the data process and Saving on SATA then the IOPS comes into matter.

all the best

>In the old days adding a fast hard disk to a computer with a slow hard disk ended up with both hard disks running at the speed of the slowest

When was that and with what interface?

As you can see from all the replies, you can easily use a primary SSD to speed up your system, depending if that was the bottleneck to begin with, obviously. If the worst bottleneck was extremely limited available RAM, a primary SSD sometimes doesn't help either.

that was back in the IDE days master/slave .  SATA has independent channels

thanks everyone

Not even with RAID did one slow disk make all the others slow down, random reads are faster with a mix of slow and fast drives than with the same amount of just slow ones. In some cases the manufacturer even encouraged mixed speeds, e.g. with HP EVAs if you had an array of 10K 300GB disks and wanted to expand it you could add 450GB 15Ks - the faster 15K disks had more work to do as more blocks were stored on them.