Laptop usb ports randomly cutting out

[Lord_Karango17]

So I recently did a reinstall of windows on my laptop in preparation for using it as a daily over the summer. After this, I notices something fairly quickly.

I use a lot of external media (2 external ssds and 2 external hdds), and while these were being used, the usb ports on the laptop would cut out for a few seconds. This happens over all the usb ports, as my external keyboard goes dark, and my mouse stops working as well.

 

Razer does not have any specific usb drivers, and I installed all the drivers that were available (excluding the graphics related ones that i got off nvidia's  website).

 

After a bit of research, a lot of people said it was a usb 3 power saving measure derping out, so I disabled anything related to usb power savings, and I also disabled "legacy usb support" in the bios to no avail. It just cut out on me while typing this, because origin opened in the background and accessed the hdd.

[Huntsman]

Get a powered USB hub. The laptop has a finite power budget for USB. All the external devices probably gone over that, especially during read/write operations.

[Lord_Karango17]

25 minutes ago, Huntsman said:

Get a powered USB hub. The laptop has a finite power budget for USB. All the external devices probably gone over that, especially during read/write operations.

Thats what i first thought, but this happens even if the external driver is directly connected to the usb port. If im not mistaken the ssds should require less than 500mv from the usb port. 

Also if one device went over the power budget, would that cut power to every single usb port?

 

Edit: Now that i looked at the power draw of the 840 and 850 evo, they both take over 1 amp, so it would make sense that they would mess with the usb ports under a heavy load. One thing is that they worked fine without external power on my desktop, and most of the usb ports on the z77 sabertooth are the normal 5v 500ma variety.

[Huntsman]

Because of limited space and power you can draw in a laptop (and probably manufacturers cutting corners too), it doesn't matter if you have 2 or 10 USB ports, they are given one power budget to share among all ports. So although in theory one should be able to draw the max current from each individual USB port, it doesn't work that way. It's more like all USB ports are allocated say (don't quote me on the numbers) 2A to be shared among all ports. Also, most laptops having one host controller for all USB ports further aggravate the issue.

 

Mechanical HDDs alone take 1A at peak, not sure about SSDs though. So it would explain your condition whereby it works fine on idle but whenever there are drive activities the USB voltage tanked and everything connected gets "restarted". You could do a rough check by probing the 5V lines with a multimeter on voltmeter mode.

 

So to answer your question, it depends. If one device went over the power budget, it wouldn't cause power cut to all other ports. BUT, when the total power draw of all ports exceed the total allocated power budget, power will be cut or there will be a significant voltage droop which causes faults.

[Lord_Karango17]

Just now, Huntsman said:

Because of limited space and power you can draw in a laptop (and probably manufacturers cutting corners too), it doesn't matter if you have 2 or 10 USB ports, they are given one power budget to share among all ports. So although in theory one should be able to draw the max current from each individual USB port, it doesn't work that way. It's more like all USB ports are allocated say (don't quote me on the numbers) 2A to be shared among all ports. Also, most laptops having one host controller for all USB ports further aggravate the issue.

 

Mechanical HDDs alone take 1A at peak, not sure about SSDs though. So it would explain your condition whereby it works fine on idle but whenever there are drive activities the USB voltage tanked and everything connected gets "restarted". You could do a rough check by probing the 5V lines with a multimeter on voltmeter mode.

 

So to answer your question, it depends. If one device went over the power budget, it wouldn't cause power cut to all other ports. BUT, when the total power draw of all ports exceed the total allocated power budget, power will be cut or there will be a significant voltage droop which causes faults.

Its becoming clearer now. I left the power adapter for the usb hub back in my dorm, but its a general 5v adapter, so I should be able rummage around for a 5v 1a/2a adapter that fits the socket.

[Huntsman]

My advice is to get a good quality USB hub with external power. Cheap ones might get you into trouble too. Check out this video.