Today Intel officially introduced the fourth generation of its Core processors, also known as Haswell. Back in March we reported on a USB 3.0 problem with the new 8 series chipset used on motherboards for desktop Haswell processors. Our recent tests confirm that this problem does indeed exist, with more than half of the USB 3.0 peripheral devices we used.
The current 8 series chipsets, C1, has a bug in its integrated USB 3.0 controller. Connected USB 3.0 devices based on one or more controllers - it's unclear exactly which one - will briefly disconnect and reconnect when a PC wakes up from standby (S3). This can pose a problem if you had a file open that's located on a USB 3.0 storage device, as the software will tell you that the file cannot be found after your computer comes out of standby mode.

The problem is not with the Haswell processors, but with the 8 series chipsets
Intel sees the issue as annoying but not as a deal-breaker, and we tend to agree. We're able to reproduce the problem, but can't really think of many scenarios in which it will be huge problem. All you have to do is to open the file again, and no data can be lost.
We tested 22 USB 3.0 memory sticks, USB 3.0 external hard disks and USB 3.0 external SSDs. 14 out of the 22 devices exhibited the problem.
| Brand | Product | Test |
|---|---|---|
| Adata | S102 Pro Superior Series 32GB | OK |
| Corsair | Flash Survivor Stealth 32GB | OK |
| Corsair | Flash Survivor Stealth 64GB | error |
| Corsair | Flash Voyager GT Short 32GB (USB 3.0) | OK |
| Corsair | Flash Voyager GT Speed 32GB | OK |
| Corsair | Flash Voyager Slider 32GB | error |
| Corsair | Flash Voyager Slider 64GB | error |
| Freecom | Hard Drive Quattro 3.0 1TB USB 3.0 | OK |
| Icidu | Rubber Drive 32GB (USB 3.0) | error |
| Icidu | Slider Fast Flash Drive 32GB | error |
| Icidu | Slider Fast Flash Drive 64GB | error |
| iomega | Prestige 500GB USB 3.0 | error |
| Kingston | HyperX Max 3.0 64GB | error |
| LG | HXD7 500GB USB 3.0 | error |
| Philips | USB Flash Drive Snow Edition 64GB | OK |
| Sandisk | Cruzer Extreme 32GB | error |
| takeMS | MEM-Drive Easy III 64GB | error |
| Team | TP1023 Rico 640GB USB 3.0 | OK |
| Team | X101 USB 3.0 32GB | error |
| Verbatim | Store'n'Go V3 32GB | error |
| Verbatim | Store'n'Go V3 64GB | error |
| WD | My Passport Ultra 500GB USB 3.0 | OK |
If you want to be sure that you buy a motherboard without that issue, you will have to wait. Intel has indicated that, starting end July, a new version of the chipset, C2, will be supplied to the motherboard manufacturers. Then the motherboards have to be produced and shipped, and retailers will of course first sell their existing stock.
You can't tell by the exterior whether a board is C1 or C2. The manufacturers are also of the opinion that it's insignificant and we haven't heard any plans that it will be mentioned specifically on the box which version it is. Once you've bought a board, you can find out which one you have with CPU-Z. Under the tab Mainboard you can see the revision of the chipset. Revision 4 is C1, and the improved C2 stepping will be called revision 5.
You can read more about this and everything else there is to know about the new chipsets and motherboards for Haswell processors, in our big test of 33 Haswell-compatible motherboards.

Chipset revision 04 is C1 with USB 3.0 bug. Revision 05 is C2 without bug.
