On the occasion of October 31, I offer you a fairy tale about how they fought with evil forces, which did not settle where it should be.

Fairy tale

He lived in one kingdom wise king. Once he decided that there were few four knights in the service, even though everyone could remember four gigabytes of information at once. The king decided to upgrade the composition of the round table, since there were already eight knights in the fortress. For a long time he chose strong, strong, reliable warriors in an overseas state: those who were not afraid of dragon's flame or hard work chose him for a squad of eight good fellows of eight gigabytes each: Kingston HyperX Fury 1867Mhz.
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The knights came to the castle, with honors sent the experienced warriors to retire, began to sit down at the round table, and they began the first difficulties. As the roll call in POST'e - so eight of them. As it comes to work, the total memory capacity is no more than 48 gigabytes, and six of them work, but two are not visible. As they did not sit at the table, together, in four, in six, on those places, on these - nothing changed.

The morning roll call was normal, but it was impossible to fight: no two, and that's it. They went to the magician and the wizard, he showed them on a wonderful device, called the monitor, the Internet miracle book, in which all the answers were all. To begin with, they tried to reduce the frequency to 1600/1333/1066/800 megahertz.

They decided to upgrade the table and chairs: the new version of UEFI should allow 128 GB of memory to be used immediately. Did not help. Then they decided to increase the salary: they raised the voltage on the memory controller, on the modules themselves, on the control system - no result. They tried to stop paying the mighty wizard, hiring his apprentice for pennies: the effect is zero, it doesn't work in the eight, although you burst, you had to take the sorcerer back.

Not enough of their strength - ask for help and experienced warriors. They called four pensioners - they all work together perfectly, and there are eight of them at the roll call, and at the table, that's just the total frequency - 1333 or 1600. You can, of course, live, but the problem must be solved somehow. Then someone said that the black dragon could be to blame for sitting in the basement. They unhooked it from the leash and shackles, and he gripped powerfully at the base of the tower. Twisted his wings and feet, but expelled from the kingdom. And at once the work was adjusted and all eight knights could calmly sit down at the table, and with a full memory in front of the sovereign to trump. But then the dragon was allowed back, so be it, let him live.

Moral tales: check not only obvious things, but also unobvious.

Literary work analysis

Not so long ago, I decided to expand the reserves of RAM to 64 gigabytes, chose a set of Kingston 's that never failed me: 8 dies of 8 GB each, 1866 MHz.

I came, I put it, I look - in UEFI it is displayed that all eight slots are occupied, but the total amount is only 48x1024 MB. And in UEFI, and in the system. At first I sinned for memory, took out two modules - still 48. I took out the other two, put in their place the removed ones - 48. Two more - 48. In general, all the connectors and all the dies were in good order, in any combination of 8 or 6 modules the system was visible only 48 gigabytes.


^{I ask pardon for the quality of the illustrations, it was not before the photo shoot, I picked up the phone from the intercom.}

It is clear that the second logical step was to check the BIOS / UEFI updates: I downloaded the latest beta version, which directly indicated support for up to 128 GB, installed - no effect. Then I had to google. Some of the materials indicated insufficient power, and some indicated a low voltage of the memory controller, which, in principle, could directly follow from an insufficiently powerful power supply unit. I checked by turning off the main consumer - the video card. All the same 48 gigabytes. Raised the voltage on the power controller, on each plate and, a little, on the processor cores - all the same 48.

I tried to use the " MemOk! " Button on the motherboard, which starts self-diagnosis and auto-fitting of memory parameters. Of course, it did not help. Like Asus OC Tuner, which squeezed out of the processor almost 5 GHz, but did not start the RAM.

I wrote both supporters: both Kingston and Asus confirmed that I was moving in the right direction - they offered the same solutions to the problem, answered quickly and in essence.

He began to sin again at the nurse, decided to check what would happen if you insert 4x4 + 4x8 - all modules are visible, the volume is 48 (as it should be), everything is fine. Put back 8x8 - 48.



The latest device that could affect the performance of the RAM was the OCZ's PCI-Express SSD disk: the SandyBridge-E memory controller and the PCI-E controller are on the same chip, in the uncore part.



I forgot to think about it, and I changed the video card during the tests, so the last thing came to the SSD. I turned off the power supply unit, uncoupled the disk, checked everything for the hundredth time, clicked the toggle switch ... A miracle, everything started up: 64 gigabytes appeared in the system, working at their maximum frequency, without any tambourine and voltage boost. I decided to test the hypothesis, put back the SSD - everything works.


^{The test results are encouraging, almost 50 GB / s for reading and 55 for writing.}

With the SSD inserted, I turned the memory dies - again 48. That is, installing SSD -> RAM - does not work, RAM -> SSD - everything is fine. So, it would seem, completely unrelated things turned out to be in extremely close correlation. Hopefully, the description of my troubles will be useful to anyone, although not everyone has PCI-E disks and a mother with an X79 chipset. Well, those who “have long wanted, but did not dare” - 256 GB PCI-E drives in speed did not go very far from SATA-III, especially inexpensive (which are single-board and without internal RAID), but the problems are delivered in order: then there are no UEFI-compatible drivers and the system is not installed normally, then they add 10 seconds to the boot time, since are initialized before POST, and the PCI-E lines are loaded. As it turned out, more and affect the memory. So read reviews and tests of SATA-III drives and do not bother with such toys, if you are not 100% sure that you need it.