Usb 3.0

whs · 02 Feb 2011

GeneO said:

whs said:

Sygnus, The USB3 cable seems to be sturdier than the USB2 cable - at least the one I have. That would suggest a bigger diameter. My tests showed a 30% faster speed with /3 over /2 when making an image of 20GBs. And that was with a 5400 RPM HDD that I recovered from my laptop when I installed the SSD.

HDD transfer rates are slower than either SATA II or SATA III.

GeneO, this is not quite correct. Transfer rates of spinning disks go to 80GB/sec and even higher - that corresponds to appr. 800Gb/sec. The USB2 can only transfer 480 Gb/sec maximum. So in that case the disk can "deliver" faster than the USB2 attachment can transport.

Night Hawk, access time is a function of the disk - the attachment does not do anything for that.

Why are you talking USB 2.0? This is a USB 3.0 interface. And HDD drives nowadays are in excess of 90 MB//s (I assume you meant 80 MB/s and not 80 GB/s like you typed).

Yeah right. Thanks for pointing that out. At least I was consistent and made it GB in all places - LOL. I corrected it.

sygnus21 · 02 Feb 2011

whs said:

Sygnus, The USB3 cable seems to be sturdier than the USB2 cable - at least the one I have. That would suggest a bigger diameter.

Yeah the cables I got with my case were heavier as well.

whs said:

My tests showed a 30% faster speed with /3 over /2 when making an image of 20GBs. And that was with a 5400 RPM HDD that I recovered from my laptop when I installed the SSD.

Well there you have it. I believe that's what the OP was looking for.

Thanks for the feedback.

Peace.

timlab1955 · 02 Feb 2011

Specs been check, all 3 devices are 3.0 and drivers are in. All 3 drives are Sata II 3GB/Sec. Now are we all on the same page?

whs · 02 Feb 2011

timlab1955 said:

Specs been check, all 3 devices are 3.0 and drivers are in. All 3 drives are Sata II 3GB/Sec. Now are we all on the same page?

That is useful information but does not really tell us the speed of the disk. It is probably in the 60 to 80 MB/sec range which would be typical for spinning disks. Another parameter we do not know is the size of the records - that could play a role in your low write performance.

I have been looking back at your very first post. Your first question was whether anybody got to 3Gb/sec (not GB -- 3Gb equal appr. 300GB). - That will never happen with spinners that run at 80 to 100GB/sec at best.

The 10MB/sec write speed is slow indeed and would need investigation. The 60 to 70MB/sec would, however, be normal. That is all the disks can probably pump.

Here is your first posts copy:

Has anyone gotten their USB 3.0 speed up to at least 3GB/sec yet? I have two 2TB extrnal hard drives and on my lap top I have 2 ports for 3.0. But when I send information out to the HDD's I get speeds like 10MB/sec. When I ask one extranal HDD to send information to the other extranal HDD I get speeds like 60-70MB/sec. How come I'm not getting speeds like I've read?

timlab1955 · 02 Feb 2011

Here is a picture of my computers HDD. The Seagate and the Iomage has both the same spin as my computer HDD.

whs · 02 Feb 2011

Nice picture which I unfortunately cannot read - too faint (too little contrast) for my eyes.

GeneO · 02 Feb 2011

Night Hawk said:

GeneO said:

Night Hawk said:

The ATA hardware limitations is what WHS is referring to there. The speed you see listed for 3.0 is the maximum you could see not the actual in use speed.

A Sata III drive for example in an external enclosure would be the preferred over any Sata II drive with that seeing the 6gb over 3gb capability but still not end up seeing more then what the usb bus supports. The transfer rate is rated twice as fast as Sata II.

The SSDs are obviously fastter but will still be limited by the bus if the speeds exceed that. But external drives are not sold with performance in mind but typically see the more energy saving model drives in use there. For WD that would be a Green Power model over a Caviar Blue or Black edition performance model.

There is absolutely no reason to prefer a SATA III drive over a SATA II drive. Transfer rates for Hard Disk Drives will be the same for SATA II or SATA III interfaces. Either protocol can handle the rates of current and future Hard Disk drives, whether it is an external or internal enclosure.

Simply staed: HDD transfer rates are slower than either SATA II or SATA III. The only reason to prefer SATA III over SATA II is for SSD drives, which can outperform SATA II rates, unlike HDD which don't. In any case USB 3.0 will be the limiting factor in that case, so again - no reason to prefer SATA III over II for an external drive.

Well I can tell you a little story on that one. When first putting this case together 7 went onto one of the Sata III drives until the memory was found incorrect forcing a new clean install on one of the Sata II drives instead. Note the Sata IIIs were plugged into the S3 ports.

What big difference was seen with 7 during the first install and later on the present host/boot drive? NONE!

What does that mean? The faster bus "allows at times" faster transfer/access times when all conditions are met. Ideal speed with ideal conditions met.

As for hard drives they are still limited by the ATA contraints of that standard. And of course one reason why people are looking a lot at SSDs being solid state over physical platters to surpass the physical limitations seen with the ATA 100/133 standard.

Well I ( and many other see no difference). Perhaps it was a difference in the device drivers you had for the 3 vs 2.

timlab1955 · 02 Feb 2011

whs said:

Nice picture which I unfortunately cannot read - too faint (too little contrast) for my eyes.

If you click on the picture you'll be able to blow it up. As for the drivers, they are all up to date. I guess I'm doomed.

whs · 02 Feb 2011

If you click on the picture you'll be able to blow it up

I know - that's what I always do. And I have all the maximum settings like different screen resolution, DPI at 150%, browser at 125%, etc. But if there is little contrast, it is still nearly impossible for me to decypher - who puts white writing on a fair grey background - not a good idea.

sygnus21 · 02 Feb 2011

whs said:

If you click on the picture you'll be able to blow it up

I know - that's what I always do. And I have all the maximum settings like different screen resolution, DPI at 150%, browser at 125%, etc. But if there is little contrast, it is still nearly impossible for me to decypher - who puts white writing on a fair grey background - not a good idea.

Agreed. Not eveyone has the great eyesight they once had (me). Even though I can read it it is a little hard on the eyes.... and this is with my reading glasses