Question Difference in transfer rate

[DanielCNP5]

Well, I'm about to spend some money on a setup, but came across a major question.
I found two HDDs. Both SATA. Very different storages. One 20 TB and the other 8TB.

But what's intriguing are the specs.
4TB one says 3000 megabytes per sec
20TB says 285 megabytes per sec but they also include the rotation speed (7200)
The 4TB, which is 10x faster doesnt even include the rotation speed.

so why such a diference?

thanks in advance

 

[USAFRet]

Well, I'm about to spend some money on a setup, but came across a major question.
I found two HDDs. Both SATA. Very different storages. One 20 TB and the other 8TB.

But what's intriguing are the specs.
4TB one says 3000 megabytes per sec
20TB says 285 megabytes per sec but they also include the rotation speed (7200)
The 4TB, which is 10x faster doesnt even include the rotation speed.

so why such a diference?

thanks in advance

Link to these?

If spinning HDD, the 4TB listing is lying.

 

[Grobe]

My guess you're testing a SMR drive vs. CMR drive in writing that give little sense to compare as SMR always show poor performance on random writes.

 

[Bob.B]

Well, I'm about to spend some money on a setup, but came across a major question.
I found two HDDs. Both SATA. Very different storages. One 20 TB and the other 8TB.

But what's intriguing are the specs.
4TB one says 3000 megabytes per sec
20TB says 285 megabytes per sec but they also include the rotation speed (7200)
The 4TB, which is 10x faster doesnt even include the rotation speed.

so why such a diference?

thanks in advance

Are you sure the 4TB is talking bytes and not bits?

 

[kerberos_20]

3000 megabytes per second is nvme, not sata for sure