I sat down this afternoon to upgrade the RAM in my Maximus VI Impact, having got some at Christmas. I have been using a 4GB stick [Crucial DDR3 1866 Tactical Tracer] in Slot 2 and added another (that has been working fine in another PC) into Slot 1. The PC wouldn't boot and showed a POST code error 55 on the LED, which means memory problem. It will boot with either stick or a 4GB stick of Crucial DDR3 1600 Tactical in slot 2, but anything in slot 1 locks it up. I cannot see any damage, and have brushed the contacts, not joy. I guess I have a dead slot, as I can't see what else it can be. Annoyingly I bought it used a while ago and never tested the other slot, as I only had 1 RAM stick, and the board ran fine from the start. And as it's ITX, of course I have nowhere else to go. Anything I've missed?
Could be a finnicky motherboard, like my X58-USB3. I've had a RAM problem a couple of times, and the ONLY way to fix the lock-up (exact same symptoms as you describe) is to go through a process of installing the modules in a particular order. If I don't do it a specific way, the PC simply will not boot into Windows. The motherboard had some really strange behaviour at times - eg with three modules installed (it's a tri-channel memory system) BIOS would say I had 4GB installed, and the description of which slots were populated and with what size of module were waaay off. Despite this niggle, the mobo has been working perfectly for almost a year with all six memory slots populated. It could be worth flashing your BIOS in case there's a problem there, or at least have a go at resetting CMOS by leaving the battery out for a few mins. As you say, it could simply be a faulty slot.
The second slot is going to be a different channel, so try re-seating the CPU and check the pins (and cpu pads) for signs of damage and such.
Thanks for the input guys, that's what I love about this place. A friend has suggested re-flowing the DIMM slot, but that sounds hairy! Interesting, I hadn't thought about these 2 possibilities. I'll very carefully pull the CPU tomorrow and see if there's anything in the contact department. Was annoyed earlier, but it still works fine at 4GB RAM and 8GB would only be for Photoshop - it is gaming fine.
Unless you clearly see a pin with a dry solder joint, I wouldn't risk it, especially if you're talking DIY oven reflowing (DIMMs are wave soldered, so I'm not sure if paste and regular solder even reflow at the same temp??). In short, a motherboard with a bad DIMM slot, is better than a doorstop, so don't exacerbate the problem.
Thanks, I think that is wise advice. I will leave well alone. It's fine on 4GB, just frustrating that I can't double up with the other stick I got for it.
