Although this topic is already well explained, I bought a refurbished hard drive and figured I would post some results. I also questioned whether I should post this or not because of the results, but I did anyhow.
Drive one (C Kingston A400 240GB SSD.
Sata iii
170gb of 240gb full.
345 hours powered on
782 power on count (i restart often)
Purchased new just a few months ago.
Drive two (D Seagate barracuda 7200RPM 750GB (ST3750528AS)
Sata i
16248 Hours powered on
28 power on count
Completely empty fresh format
Purchased refurbished just days ago.
Both have good health in Crystal Disk info as of the beginning of this test.
Drive two would be representative of an average hard drive from an older system that has been used for a while.
Drive 1 would be representative of a new SSD you would buy.
Drive 2 actually has an advantage since it is blank and the OS is not affecting benchmark speeds unlike drive 1, however, this does not help it much, spoiler.
Here are Crystal Disk Mark results.
Drive One:
https://ibb.co/PCtG75V
Drive Two:
https://ibb.co/Wn8qXGh
As you can see, the performance of the hard drive is 5 times slower in sequential reads, but as much as 250 times slower as much in random reads. This is a lower-end SSD is humiliating the hard drive.
However, I opened Crystal disk Info again after this test and noticed, the Seagate HDD now shows "caution" and 100 reallocated sectors. I got a refund, but this isnt to uncommon with older drives.
So your old hard drive may be hurting both your performance and reliability.
Just a few flaws with this test.
HDD condition deteriorating could have tanked performance, but this demonstrates a reliability point.
Different load on the drive from OS and different amounts of data written.
An older drive may be in a system with support for only older versions of SATA, which could slightly diminish the performance increase of the SSD.
Also, this SSD is a replacement for the original one which died after a year. So maybe I just have bad luck with drives?
Drive one (C Kingston A400 240GB SSD.
Sata iii
170gb of 240gb full.
345 hours powered on
782 power on count (i restart often)
Purchased new just a few months ago.
Drive two (D Seagate barracuda 7200RPM 750GB (ST3750528AS)
Sata i
16248 Hours powered on
28 power on count
Completely empty fresh format
Purchased refurbished just days ago.
Both have good health in Crystal Disk info as of the beginning of this test.
Drive two would be representative of an average hard drive from an older system that has been used for a while.
Drive 1 would be representative of a new SSD you would buy.
Drive 2 actually has an advantage since it is blank and the OS is not affecting benchmark speeds unlike drive 1, however, this does not help it much, spoiler.
Here are Crystal Disk Mark results.
Drive One:
https://ibb.co/PCtG75V
Drive Two:
https://ibb.co/Wn8qXGh
As you can see, the performance of the hard drive is 5 times slower in sequential reads, but as much as 250 times slower as much in random reads. This is a lower-end SSD is humiliating the hard drive.
However, I opened Crystal disk Info again after this test and noticed, the Seagate HDD now shows "caution" and 100 reallocated sectors. I got a refund, but this isnt to uncommon with older drives.
So your old hard drive may be hurting both your performance and reliability.
Just a few flaws with this test.
HDD condition deteriorating could have tanked performance, but this demonstrates a reliability point.
Different load on the drive from OS and different amounts of data written.
An older drive may be in a system with support for only older versions of SATA, which could slightly diminish the performance increase of the SSD.
Also, this SSD is a replacement for the original one which died after a year. So maybe I just have bad luck with drives?