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CRowl1
Beginner
1,631 Views

Does anyone know the maximum total current draw across all USB ports on the DZ87KLT-75K or Z87 Chipset?

My understanding is that any host USB 2.0 connection should be able to supply up to 500mA of power to a USB device. However, is it possible draw too much current from the controller? For instance, if the controller is connected to the maximum number of devices (in this case 14) and each is drawing 500mA, could this affect the performance of the controller? I couldn't find any total maximum spec on this board. I was looking at the spec for the ICH10 chipset. It offers I think 12 USB (I think some USB 3.0 and some USB 2.0, which might have different current specs) ports. As a thought experiment, let's say that they need to have 500mA for each port. This would mean that the controller would need to draw 6As at 5Vs somewhere in it's maximum specs. However, I don't see anything close to that in the spec (granted it would be easy to miss as the specs are hundreds of pages long). And at lower voltages, I'd expect to find an even higher current draw which I couldn't find either.

Any help would be appreciated! Thanks!

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5 Replies
Silvia_L_Intel1
Employee
64 Views

Rowlett, I going to check on this and I'll keep you posted.

CRowl1
Beginner
64 Views

Awesome. Thanks! We've seen some kind of wonky behavior from these boards in general (particular having to do with the USB devices). However, we are pushing these controllers to what could be their limits so I just want to make sure we aren't outside of their spec before proceeding.

Silvia_L_Intel1
Employee
64 Views

Rowlett,

I am pretty sure that what you may need to get is a bigger power supply (more wattage) and include more memory RAM on the board.

 

Please remember that this board supports a maximum of 32GB of DDR3-1600 and 1333 Mhz.

 

Regards.

 

CRowl1
Beginner
64 Views

We currently run a lot of memory (16GB) and never approach even 50% usage. Regarding power, we use a 500W PSU and have to support a 3770K proc, 4 DIMMs, a couple drives, an nVidia GT 520 and a few cards.

We can calculate worst case power consumption (which never occurs). The GT 520's maximum power consumption is around 31W. The 3770K is tested to use around 160W (though this number is dubious). DIMMs we'll cap at 15W per module, so 60W. The mainboard we'll cap at 100W. We have three cards which cap at around 50W total. And then we have a DVD Drive which we'll cap at 20W. This is all worst case, which the computer almost certainly never reaches.

Totalling gives 421W. We have 10 USBs accessible on the case. If all of those are supplying 500mA, then 5V * .5A * 10 = 25W total power consumption (though this situation doesn't actually occur, and this doesn't factor in USB3 high amperage or any peculiarities in the amperage provided by these ports). This puts our system load at 446W at the worst case. We could get a 100W increase in our power supply but I'm very skeptical that the power supply limits are ever reached and actual usage is much lower, though depends on operation.

I'm surprised there isn't some absolute max spec for the draw on the USB ports. If there isn't, I'll have to assume the board itself is actually faulty. Thanks for the information.

- Chris

Silvia_L_Intel1
Employee
64 Views

Chris,

Intel motherboards complies with USB standards, therefore each port will draw a max of 500mA.

For example if you are using a 1000W power supply, and you included 14 USB devices on the motherboard, since, each USB will draw 500mA at the same time, the max throughput may be affected, but the motherboard will maintain all 14 ports working.

Power supply shows maximum power utilization, however that value is not absolute, it is a nominal value. Therefore, the maximum power can vary about 10% to 15% less. That range could decrease if the PSU is 80plus certified

Please be aware this answer applies for any 7th or 8th series boards. Just in case you are using a 7th series motherboard with the I7-3770K processor you included on your post.

Regards.

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