Same here.  There are at least 4 threads on the first 4 pages of these forums about this very problem.

My computer ran like a dream for 6 months.  No OC.  Bios at defaults.  Then it started like a week ago.

My keyboard loses power for about 10 seconds every couple of days. Really sucks when you lose your keyboard while your gaming.

Mine does it too

Sometimes it doesn't come back and I have to reboot.  Sometimes I reboot and it won't recognize me hitting DEL to get into bios.

d that at a certain point, for their bclk to hold they have to increase the pcie clock. Setting above 102-105 can start exhibiting these drop out problems depending on the sensitivity of the hardware installed on the usb port.

My bios is set to default.  Everything ran fine until about a week ago.

I have this problem with my E758 motherboard. Approximately 50% of the time when I do a hot insertion (USB Flash drive, BlackBerry, or some other bus-powered USB device), there may or may not be the "OS Sound", and all USB devices stop working (not just the device I inserted, but also the mouse and keyboard). I switched my keyboard to a PS2 variety, so that I can use it to shutdown the system when all my USB devices freeze (Windows key, then right-arrow key, then Enter key). I have learned to never have ANY applications open when I insert my USB Flash drive or my BlackBerry.

Now if I have the USB Flash drive plugged in before I power-up the computer, the USB Flash drive is ALWAYS functional (once I get into Windows, of course). I can not plug in my BlackBerry before I power-up the computer, as the 3 times I tried that, it "crashed" my BlackBerry and I had to remove its battery to recover. Very frustrating.

To avoid the problem as much as possible, I have addes a PCI add-in USB card that I have my printers, scanner, and memory card reader plugged into. I have also added an exteranl self-powered USB hub that I have connected to one of the USB ports on the E758 I/O panel. Since it is plugged in and powered-up before the computer is turned on, it always seems to work fine - and this is now the only place that I plug in my USB Flash drive or my BlackBerry. (OK, once every few days I'll still try the case's front USB ports, just to remind me that they still don't work 50% of the time.)

My normal BCLK is set to 180, but it also occurs the same percentage of the time when at the stock BCLK of 133. My PCIe frequency has been 100 and 101, never anything else. I have raised my ICH VCore from 1.050V to 1.075V, 1.100V and even 1.125V - sometimes I think it helps a little, but none of them vary the success rate significantly - so now I jsut leave it at 1.075V. I also played with IOH/ICH I/O Voltage, raising it from 1.500V to 1.600V, but it did not make any difference, so now it is back at AUTO (1.500V).

I keep thinking that "tonight is the night I finally call EVGA support" about this issue and request and RMA, but EVERYTHING else with this motheboard and system is working perfectly. I'm dreading the idea of taking the entire system apart, shipping the motherboard off, waiting a week while not having a computer, and spending the 2 or 3 hours to put it all back together - and the fear that I will then have some other "new" problem to deal with.

That's odd.  Like the usb port isn't getting enough power to it.  Could be the bios or physical on the mobo.

its happening again :( on stock settings too no OC :(

Is this a driver issue or a hardware issue?  I have heard of this happening on some of the P55 motherboards as well.

Please let us know how your ticket turns out.

This sounds voltage related to me. Like there is just not enough juice. Ulim8 looks to have plenty to spare in his HX1000, maybe its just not getting to the ports!

I have random USB dropouts when I start Windows on my E757. Sometimes it works perfectly, but other times at least one of my USB devices drops out. However, something interesting I noticed is that while the mouse won't move the cursor, I can still occasionally use the button(s). This happens on both the onboard USB ports and the extra two that go near the PCI slots, and the only way to fix it is to unplug the device and plug it back in.

I have had similar issues, intermitten sound issues w/ loss of sound when watch tv from the internet, usually when I'd try to full screen.
But other sound issue as well.  Also excessive heat issues on my GPU's. (GPUz).  And boot-up and boot down issues.   I have a wireless mouse keyboard MS ergo 7000 and the Razor Mamba.  My mobo is the 3x I think 760.  On one hand I am glad I wasn't Imagining things on the other this doesn't look good.  Help EVGA.... 

EVGA X58 3X Classified 760
Intel i7 920  3.7 OC
Mushkin Ram
Velocoraptor drive
2 ATI 5870 in crossfire
Corsair 1000HX PSU
HAF 932
Noctua
Ram fan

This may be a reach but how many of you have both 12v  8-pin power slots used on the Classified? Also, just to be sure how many of you have the necessary USB settings under "Power Options" in Vista/Win7 (Control panel) selecting "High Performance" and also disabling "USB Selective Suspend Setting", it wouldn't hurt to check this and see if it helps any. Also go into "Device manager", double-click your network adapter and select "Power management" tab and deselect "Allow the computer to turn off this device to save power"

I'm a bit worried to hear of these problems and empathetic as well especially since this board has been out for some time now with plenty of room for mature BIOS development, why is this happening? Since I'm considering ordering the 3-Way Classified soon to anchor my new build, it's also not good that EVGA support hasn't commented as of yet, hopefully some insight is forthcoming.