How a shitty, buggy BIOS fried my CPU, without even overclocking it.
Last month (December 2015), I decided to upgrade my desktop and buy myself a 6700k, with 16GB of DDR4 memory.
Having a micro ATX case, I didn't have much choice of motherboards, it was either the ASUS Maximus VIII Gene, some Asrock, and the Gigabyte Z170MX Gaming 5. Despite having had issues with a crappy ASUS BIOS in the past, I decided to give them another chance, because it seemed like a nice, stable motherboard, so I spent 250 euros on the Maximus VIII Gene.
Despite looking like gaming shit, the motherboard seemed very well built: ASUS is pretty good when it comes to hardware. I plug everything in, turn on the system and... nothing happens. Great.
I wait for a while, and 30 (THIRTY!) seconds later, it boots. I enter the BIOS setup, turn on CSM because I don't want to use a UEFI bootloader, turn on hardware virtualization (which for some reason is always disabled by default) and leave everything else to auto, because I'm not familiar with the platform yet and don't want to overclock it yet. F10, save settings and reboot.
Again, nothing happens for 30 goddamn seconds. At this point I realized that this thing was taking 30 entire seconds just to POST, even with "Fast boot" turned on, so I tried updating the BIOS, but with no luck. I then looked up the issue online, and it turns out that by default it checks ALL the installed memory at boot. I shit you not, I haven't seen a computer that does that since the mid 90s. The option was also hidden between the memory latency settings, and was called "MCH Full Check", just to make sure you don't find it. I can't even imagine what the hell they were thinking. Oh wait, I know, they were too busy programming useless animations, different fades for the LEDs and doing marketing shit to actually write a proper BIOS. Again, F10, save and reboot, and this time it takes a reasonable 3-4 seconds to POST.
Everything works nicely after that, no issues at all, good temps and everything, until a few days ago, when the system crashes while encoding a video, which is very odd, considering it wasn't even overclocked. I rebooted, made sure it wasn't Windows or a driver issue, and restarted the encoding, this time while keeping an eye on the temperatures and the CPU voltage. A few minutes later, apps start crashing, the display starts glitching, and I get a blue screen of death saying UNEXPECTED_KERNEL_MODE_TRAP. I looked it up online and it seemed to be related to the CPU or the RAM, so I ran memtest for a few hours but it found no errors; then I ran Prime95, and got this interesting result: if I stressed the CPU and L2 cache, it worked fine, but when I used a lot of memory, the system would become unstable after a few minutes. And yet memtest kept saying the memory was fine. Strangely enough, nobody online seemed to have this same issue.
So at this point, I asked a friend who knows a bit about overclocking on this platform to see if he could help me figure out this problem. We entered the BIOS setup and here, the horror. By default, it had set the memory controller voltage to 1.5v instead of 1.2v. On fucking AUTO! Even after resetting the BIOS, it would still set it to 1.5v unless I set it manually to 1.2v.
This voltage is not high enough to fry the chip right away, but is definitely enough to cause damage over a few weeks to the memory controller and/or the RAM. Thankfully, the RAM I was using could take that voltage, too bad the memory controller couldn't, and on Intel systems, the memory controller is in the CPU. In other words, a bug in this stupid BIOS fried a brand new expensive CPU. What an absolute pile of fucking shit.
We set the voltage to 1.2v, but the damage was already done. Here's a funny video of the system freaking out while compressing a file:
Finally, I sent that shit back to Amazon to get a refund, and RMAd the dead CPU to Intel to get it replaced. Meanwhile I got myself a Gigabyte Z170MX Gaming 5, which hopefully will be less shit. I'll write an update as soon as I get the new CPU.
Lesson learnt, ASUS.
The new CPU is here, and it works beautifully. Surprisingly, the Gigabyte BIOS is actually pretty good (and it set the correct voltage).