USB 3.0 controller on an OptiPlex 745 Desktop

RoHe - I have an Optiplex 755 Desktop with XP Pro SP3, 4GB of RAM, an Intel E6850 Core 2 vPro processor and two cards in place at the bottom back - a video card and a low-profile fax modem card.  In the front, there's space between the hard drive and the DVD drive because I do NOT have a floppy drive.

Is there any way to make my machine also do USB 3.0?  Please point me in the right direction.  Thanks.

RoHe - I have an Optiplex 755 Desktop with XP Pro SP3, 4GB of RAM, an Intel E6850 Core 2 vPro processor and two cards in place at the bottom back - a video card and a low-profile fax modem card.  In the front, there's space between the hard drive and the DVD drive because I do NOT have a floppy drive. Is there any way to make my machine also do USB 3.0?  Please point me in the right direction.  Thanks.

Next time, please start your own new thread because you have a different model than the OP.

You have the same issues.  Without the card riser, you can only use low profile cards in either the PCI or PCI-e slots. If your video card is in the PCI-e x16 slot, you either have to install the card riser to add another PCI-e slot or use a PCI card in an empty PCI slot.  Check the manual for details about the versions of PCI and PCI-e used by this system and make sure any card you buy is backward compatible to support those versions of PCI and PCI-e.

Also keep in mind that Microsoft is no longer supporting XP with new security updates or hotfixes, so your system may be at risk for malware. Consider updating to Win 7. You can run the free Win 7 Update Advisor from Microsoft to see if your system can support Win 7.  If you stick with XP, you also need to make sure any USB3 card you buy works with XP.

I have a couple of OptiPlex 745 in the DesktopFF and I want to add a USB 3.0 controller.  I want to be able to use a USB 3.0 Blu-Ray writer and external USB 3.0 drives at the highest possible transfer speeds.  From what I see, the only way to do this on the 745 is to use the PCI-Express slot.  Is this feasible on this machine - can the power supply handle it?  I was looking at adding a card like this: http://www.amazon.com/Inateck-Express-Connector-Controller-Internal/dp/B00FPIMJEW/ref=sr_1_13?s=electronics&ie=UTF8&qid=1409930144&sr=1-13&keywords=usb+3.0+pci-e+card

FWIW, I have a client who has an OptiPlex 990 and I installed this card (the 5-port version) and it works well.  The case is large and the PC Power Supply has only two SATA power cables and they are split on the ends to support two HDDs and two 5-1/4 devices (like DVD, etc).  In my instance, the supplied SATA splitter was too short to span the distances involved so I had to buy a 12" SATA Power Extension Cable which worked out just fine.  I elected to split one of the DVD drops rather than the HDD drop because of the clearances for the HDD that required a very low profile power connector. 
At any rate, I have no complaints about the card.  It works well.  If you're not needing so many USB-3 ports, you can go with one of the cards with fewer ports and save a few bucks.  Lots of ways to use these cards and I couldn't be happier.

Good luck...