Adding USB 3.0 ports to a cheap 2008-era PC

[HriniakPosterChild]

Several years ago I bought one of these PCs.
 
I would like to yank the obsolete modem card and insert a PCI card to give it some USB 3.0 ports.  When I cracked the case for the first time a few days ago, the first obvious problem came up. USB 3.0 cards all seem to need a connection to the power supply (either via SATA or Molex), and this machine’s 160-watt power supply does not have a free power cable hanging off of it.
 
I have never built my own PC and am not experienced with budgeting power. Can I simply buy a splitter cable like this and expect it to work to power a USB 3.0 card without overusing that power supply? Or is trying to extend the life of this PC this way a bridge too far?
 
Also, any guesses what my next problem will be if I try this?
 

 

[Nick Kaufman]

I can't speak with certainty, but it seems to me that you will not have a problem. I doubt that the USB ports use THAT much power and I doubt that the manufacturer left was no leeway in the power supply.
 
Try looking for a power supply calculator online and see if one them includes a usb pci card to see how much power one of those is supposed to use.

 

[Couperin47]

That power supply should be able to handle the minimal draw of a USB 3.0 pci card. There are a ton of cheap cards of this type, they are basically one chip cards. The best performance will likely come from a card using the Renesas chipset (this is the sucessor to the chipset originally developed by NEC). Most cheap cards use chipsets by mediasonic and others that are distinctly less reliable.
This Rosewill uses the preferred chipset: http://www.newegg.com/Product/Product.aspx?Item=N82E16815166026&cm_re=usb_3.0_pci_card-_-15-166-026-_-Product

 

[Red Sox Physicist]

That power supply should be able to handle the minimal draw of a USB 3.0 pci card. There are a ton of cheap cards of this type, they are basically one chip cards. The best performance will likely come from a card using the Renesas chipset (this is the sucessor to the chipset originally developed by NEC). Most cheap cards use chipsets by mediasonic and others that are distinctly less reliable.
This Rosewill uses the preferred chipset: http://www.newegg.com/Product/Product.aspx?Item=N82E16815166026&cm_re=usb_3.0_pci_card-_-15-166-026-_-Product

 
That's a PCI-express card. He's looking at using a PCI card.
 
Don't bother getting a USB 3.0 card on PCI. The slot on your motherboard is a 32-bit PCI slot. The max bandwidth is 266 MB/s = 2.1 Gbps (32-bit at 66 MHz). With overhead, the USB 3.0 PCI cards I found are limited to 1.3 GBps. USB 3.0 is at 5.0 Gbps, so you'll be bandwidth limited by the PCI port. The total bandwidth of the card will be limited by that, so if you use more than one port, the ports have to share that total bandwith. USB 2.0 is 480 Mbps. If you use more than two ports at a time, you're doing worse than USB 2.0.

 

[Couperin47]

 
That's a PCI-express card. He's looking at using a PCI card.
 
Don't bother getting a USB 3.0 card on PCI. The slot on your motherboard is a 32-bit PCI slot. The max bandwidth is 266 MB/s = 2.1 Gbps (32-bit at 66 MHz). With overhead, the USB 3.0 PCI cards I found are limited to 1.3 GBps. USB 3.0 is at 5.0 Gbps, so you'll be bandwidth limited by the PCI port. The total bandwidth of the card will be limited by that, so if you use more than one port, the ports have to share that total bandwith. USB 2.0 is 480 Mbps. If you use more than two ports at a time, you're doing worse than USB 2.0.

 
You're, of course, correct  I didn't notice we are talking about a PCI slot. If, in fact, all he wants to do is connect a single external hard drive,  such a card will provide about double USB 2.0 bandwidth.
At Newegg I see exactly 2 such cards, a Startech and an Addonics and both are $45.  This isn't a reasonable solution if you're trying to read or write anything significant to a 2 Tb external drive....

 

[HriniakPosterChild]

Thanks for the analysis. Better not to waste time on things that won't work.

Is it a more realistic upgrade to replace the internal HD and pop in a GB Ethernet card in the PCI slot?

 

[Harry Hooper]

Thanks for the analysis. Better not to waste time on things that won't work.

Is it a more realistic upgrade to replace the internal HD and pop in a GB Ethernet card in the PCI slot?

 
 
You can certainly spend more, but you can get a cheap PCI Gigabit adapter at Microcenter:
 
http://www.microcenter.com/product/316241/TEL9901G_Gigabit_Ethernet_Adapter
 
This item was $8.99 a few weeks ago, but still under $10 now. It gets detected and auto-installed by Windows as a Realtek Gigabit Adapter.

 

[Couperin47]

Thanks for the analysis. Better not to waste time on things that won't work.

Is it a more realistic upgrade to replace the internal HD and pop in a GB Ethernet card in the PCI slot?

 
This makes more sense, but considering the BIOS of this box and the OS you're probably running, you don't want any HD larger than 2 Tb since it has to be your boot drive.

 

[HriniakPosterChild]

Yeah, 2TB will be more than adequate to extend the life of it for a few years.

 

[HriniakPosterChild]

Poking around some more, page 23 of this service manual says that the machine has a PCI-E card slot for a graphics card. It is unused right now. (IMPORTANT: Due to the small computer size, you can only install a small, low-profile PCI-E card of the same approximate size of the graphics card. HP recommends that you install a card with power consumption of 25 watts or less.) 
 
Does anyone know of a low-profile USB 3.0 card that can populate this slot, pull sufficient power straight from the bus, and service multiple USB 3.0 ports at high speeds?