Do you want to... - HotUKDeals
We use cookie files to improve site functionality and personalisation. By continuing to use HotUKDeals, you accept our cookie and privacy policy.
Get the HotUKDeals app free at Google Play

Search Error

An error occurred when searching, please try again!

Login / Sign UpSubmit

Do you want to...

£0.00 @
...build a snowman Read More
dcx_badass Avatar
7y, 6m agoPosted 7 years, 6 months ago
...build a snowman
dcx_badass Avatar
7y, 6m agoPosted 7 years, 6 months ago
Options

All Comments

(18) Jump to unreadPost a comment
Comments/page:
#1
Yep, quite normal to only need one.
banned#2
old..
#3
It will either work or it will not. Some need two ports, most will do with one. Think it has more to do with the ports than the drive.
#4
Its about voltage and current, 2.5 drives need 5volt DC and a set amount of current, But older p.c.`s and laptop (like USB 1.0) dont supply enough current from 1 USB slot, thus 2.5 drives have 2 USB connections so the drive can get the full current/power
#5
dcx_badass
But I can plug it into my desktop as sata uses the same connectors and it would get 12v from that, does the HDD regulate it.

So is the extra USB only needed for old PCs then?


No it uses the 5v line (pins 7,8 and 9)

As for why some computers need two depends on the configuration. Some need two, some pass enough amps from one and some need one off mains and two off battery.
#6
I tend to find it's Pentium4 based laptops that normally require the two plugs even though they're USB2.0, otherwise it's normally one.

John
#7
You need two usb ports one to power/transmit and receive data other for extra power, the drive will be faster with the extra usb connection. Even with the eSATA connection you still need to connect the usb to power the hard drive up.

2.5" hard drives always require at least 500ma of current - if plugged into a single USB port that port must be able to provide the full 500ma - if it can't then you must plug into two USB ports
#8
dcx_badass
I've tested it with one and with both, it was the same speed.


Yes drive dependent see my edit above your post
#9
Quote taken from expert:

The standard max of 500ma is supposed to be available from every USB port directly connected to the mboard - that's always the case with desktop mboards, and it's supposed to always be the case for a PCI USB controller card when you plug it into a desktop mboard, but in real life some laptop directly connected to the mboard ports can't deliver that much current, and PCMCIA and ExpressCard USB 2.0 controller cards you can get for laptops often cannot supply more than 500ma total for all the ports in the adapter unless an external power adapter is connected to them (some have jacks for that - they usually don't come with a power adapter if they do).

Thus if a drive does not work from one usb then it will need two, and a hub will not work because hub`s are only supplied from one usb slot
#10
dcx_badass
Kk, will be interesting to see how the drives affect it, I have a 60GB now, and a 120GB in the post and two identical enclosures.


You might find both drives will work fine (with one usb each), even if they are plugged in at the same time - if they both are getting the full 500ma current supply from the main board.

Different drives run at different speeds, most 3.5 run at 7200rpm but most 2.5 only run at 5400rpm thus less power needed
#11
aah..:oops: barging in here, where did you get the 3.5" enclosure with the usb port? i need one too...
#12
bashy2002
You might find both drives will work fine (with one usb each), even if they are plugged in at the same time - if they both are getting the full 500ma current supply from the main board.

Different drives run at different speeds, most 3.5 run at 7200rpm but most 2.5 only run at 5400rpm thus less power needed


I've never come across a machine that could drive a 5400rpm drive but not a 7200rpm drive over a single USB connection, it's always been both work or don't work.

John
#13
Johnmcl7
I've never come across a machine that could drive a 5400rpm drive but not a 7200rpm drive over a single USB connection, it's always been both work or don't work.

John


Like i said its all to do with power

Re-read all in this tread, what i said then you might understand, if all drives only need 1 USB connection then ask yourself why do they send them out with 2 usb connections, there not just for show
#14
bashy2002
Like i said its all to do with power

Re-read all in this tread, what i said then you might understand, if all drives only need 1 USB connection then ask yourself why do they send them out with 2 usb connections, there not just for show


Somewhat ironic to tell me to re-read the thread when you clearly haven't as I've explained already which machines tend to need the two USB ports (it's above your reply). It's not the drive power itself which has to conform to a set specification, the manufacturers can't ramp up the power as they see fit - the problem is the host power which is why on some machines the two USB ports are required, such as Northwood derived Pentium4 laptops. This type of machine is likely to require two USB ports for both 5400rpm and 7200rpm drives whereas modern machines can run 7200rpm drives on a single USB port.

John
#15
Wasting my time trying to explane this, Its got nothing to do with which laptop it is or isnt its all to do with power and if 1 USB slot can deliver it.

Google it !! its your best friend
#16
bashy2002;7295161
Wasting my time trying to explane this, Its got nothing to do with which laptop it is or isnt its all to do with power and if 1 USB slot can deliver it.


The problem here is you - the information you've posted you don't have a clue how any of this works, clearly you need to actually do some reading here or on Google before posting again. The reason the laptop does matter is because most of the USB ports will be driven from the USB hub on the laptop's chipset, which in turn means if there are certain common chipsets that don't provide enough power on this bus the USB hard drive will require both USB ports. In practice, this meant many of the Northwood Pentium4 laptops which rarely used a third party chipset required both USB ports but as these laptops are long since discontinued, both USB ports are now rarely required. I'm not claiming that's the only systems that require both USB ports are there are some other secondary hubs that also do (tend to find this occasionally on front mounted USB ports) but in general use it's certain older Intel chipsets that tend to crop up with the issue.

Desipte your previous comments it has nothing to do with the drive being 5400 rpm or 7200 rpm as both types of drive have to conform to the same specification. As I use 2.5in drives for backup purposes across a wide range of hardware systems which back up the 'theory' of the power requirements I understand the technology without the need for 'googling it' - instead of throwaway, sarky comments you'd do well to actually make some effort to do some reading yourself rather than give the wrong information as advice to other people.

John
#17
dcx_badass
USB gives 5v, 3.5" HDDs use 12v.


He was referring to 7200rpm 2.5" drives not 3.5" desktop drives.
#18
Gee i was only saying that a 7200rpm drive may use more power than 5400rpm unit thus 1 usb might not cope as well as 2 (poss more in older laptops)

No need to get personal about it.

Post a Comment

You don't need an account to leave a comment. Just enter your email address. We'll keep it private.

...OR log in with your social account

...OR comment using your social account

Thanks for your comment! Keep it up!
We just need to have a quick look and it will be live soon.
The community is happy to hear your opinion! Keep contributing!