Gigabyte GA-X99-UD4 boot loop
I recently bought a spanking new Gigabyte GA-X99-UD4 motherboard for a new build. Having previously used a Gigabyte in my X58 build I was happy with the quality, performance and stability of their products.
The UD4 motherboard, to me, is the sensible choice out of the X99 launch line-up. Although new boards have been released since that may be a smarter purchase (I've not looked). Gigabyte were at the front of the trend using high-quality components on their high-end boards. Solid-state capacitors, thicker copper on the PCB etc. I've seen many motherboards fail in my time, but the Gigabyte ones seem to be pretty tough even with some hot overclocking.
The UD4 in particular had a decent PCIe layout, making use of all 7 ATX expansion slots, a lot of other brands had 6 - may not be an issue, but I certainly had maxed out the expansion slots on my last build with upgrades and SLI. Keeping this flexibility is important to me. There are then other boards in the Gigabyte X99 series that are more expensive but add little for me. You can get one with Wifi built in (if you're spending money on an X99 platform, you should cough up for an Ethernet cable), or you can get one with the obscure "Killer" LAN network interface instead of the highly performing and well supported Intel gigabyte nic. Keeping with the main-stream when it comes to computers saves so much pain in the long-run. I've had so many issues with drivers for lesser well known manufacturers. Not always on day-one, but when a new OS is released, or I want to do something more than surf the net.
As often with the cutting edge, things have teething problems, as a geek I accept that this will be the case if I buy in on day one. The UD4 is no exception, but luckily Gigabyte are pretty good at rolling out beta BIOS updates to resolve issues - and my system appeared to be fine. That was until I enabled XMP on my memory. XMP is embedded settings for your memory and it's speed. Your system will run your RAM at the default settings, but performance memory is capable of so much more, exactly what is detailed in XMP on the modules. You select the profile in your BIOS and your computer gets faster. Brilliant.
In particular I was trying to use the XMP profile on my Corsair CMK16GX4M4A2666C15 memory to clock it at 2,666MHz instead of the default 2,133MHz. This worked fine until I connected USB devices to the front of my case (or directly to the front USB headers on the motherboard). I have a fan-controller and card-reader which attach here, so fairly important to me. In this situation, the system would not successfully POST (power-on-self-test), and instead get stuck in a boot loop where it would fail to boot and restart itself with default settings.
This started off really disheartening, as to start with I didn't know what was causing the issue. I had to go back to basics of unplugging everything and then putting them back in to see what would cause the problem, which is how I identified the USB ports as being the problem. I contacted Gigabyte support who asserted that the memory I am using has been tested with the board and it's probably an issue with the memory. This though clearly was not the case as the system was stable and fine with XMP - provided the front USB ports weren't connected. A previous beta BIOS (F9c) had already resolved the same boot-loop issue with the front USB ports even without XMP enabled, so the problem seemed clear.
Luckily Gigabyte provided me with an experimental BIOS - which made absolutely no difference. I went back to them and seemed to get back to first-line support again. After pushing back again all went quiet until yesterday when I received a F9f BIOS - currently unavailable on their web-site - which resolves the issue.
So - if you've stumbled across this site through search because of a similar issue, you'll need to update your BIOS to F9f, hopefully this will be on the Gigabyte web-site soon, if not you'll have to raise a support ticket with them.