BIOS does not recognize all RAM

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   Someday (i don't know exactly when) My Z68 Extreme4 Gen3 MB stops to recognizes all RAM installed. But cpu-z does. Even memtest see 4 sticks, but summary show only 2 of them. I try to check sticks one by one, the all working, but somehow when i inserts one the others disappears. I updated the bios, i reseted the bios many times, but it wasn't helpful.
I have 4 stick - 2x2GB and 2x4GB.
one sticks
https://www.corsair.com/eu/en/Categories/Products/Memory/High-Performance-Memory/Vengeance®-Low-Profile-??8GB-Dual-Channel-DDR3-Memory-Kit/p/CML8GX3M2A1600C9#tab-tech-specs
other sticks
https://www.corsair.com/ru/ru/?а?его?ии/??од?к??/?од?ли-пам??и/?од?ли-пам??и-в??окой-п?оизводи?ел?но??и/Vengeance®-Low-Profile-Blue-??4GB-Dual-Channel-DDR3-Memory-Kit/p/CML4GX3M2A1600C9B#tab-tech-specs
On the site i see identical specs, but cpu-z shows that sticks has different timings...
Setting lower mem freq doesn't help too.

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emoxam Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 14 Mar 2022 Status: Offline Points: 50	Post Options Post Reply Quote emoxam Report Post Thanks(0) Quote Reply Topic: BIOS does not recognize all RAM Posted: 14 Mar 2022 at 1:59pm
	Someday (i don't know exactly when) My Z68 Extreme4 Gen3 MB stops to recognizes all RAM installed. But cpu-z does. Even memtest see 4 sticks, but summary show only 2 of them. I try to check sticks one by one, the all working, but somehow when i inserts one the others disappears. I updated the bios, i reseted the bios many times, but it wasn't helpful. I have 4 stick - 2x2GB and 2x4GB. one sticks https://www.corsair.com/eu/en/Categories/Products/Memory/High-Performance-Memory/Vengeance®-Low-Profile-??8GB-Dual-Channel-DDR3-Memory-Kit/p/CML8GX3M2A1600C9#tab-tech-specs other sticks https://www.corsair.com/ru/ru/?а?его?ии/??од?к??/?од?ли-пам??и/?од?ли-пам??и-в??окой-п?оизводи?ел?но??и/Vengeance®-Low-Profile-Blue-??4GB-Dual-Channel-DDR3-Memory-Kit/p/CML4GX3M2A1600C9B#tab-tech-specs On the site i see identical specs, but cpu-z shows that sticks has different timings... Setting lower mem freq doesn't help too.

threadzipper1957 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 05 Mar 2022 Status: Offline Points: 9335	Post Options Post Reply Quote threadzipper1957 Report Post Thanks(0) Quote Reply Posted: 14 Mar 2022 at 10:46pm
	Hello, The memory controller is NOT on the motherbaord but integrated in the CPU, and the system can set only one value that is applied to all the slots. When memory is mixed, it can happen that it simply will not work. The memory modules contain a socaleld Serial Presence Detect (SPD) chip, which contains informationm anout the chips that are used, what brand, ranking and size, and the old fashioned JEDEC (also called SPD) profile and often an XMP overclocking profile. The BIOS shows only what is written in the SPD chip, and that is why in BIOS you see usually all RAM, but Windows uses it in a different way, and usually only 2 of 4 sticks, will be shown. Keep in mind Corsair is not a true memory manufacturer, the buy the PCB's and the chips, from Companies like Samsung, Micron, Nanye, Elpida, Spectek, Hynix and others, so chips on each batch can vary. But this is not a deefct of the baord, but a compatibility problem between the memory controller inside the CPU, and the memory
	Kind Regards

emoxam Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 14 Mar 2022 Status: Offline Points: 50	Post Options Post Reply Quote emoxam Report Post Thanks(0) Quote Reply Posted: 09 Apr 2022 at 9:10pm
	This memory worked 13 years, and one day stopped. There is nothing about combability. Bios doesn't show all 4 modules, it shows only a half of it. But i can change modules from 1 and 3 slots to 2 2 and 4 and it will work, i can use one by one and it will work, i can use one pair of sticks or other in any slots and it will work, but all 4 sticks in all 4 slots stoped to work. When i insert stick in slot 4 the stick in slot 3 disappears, an the same happens with slots 1 and 2. Seems that stick in 2 and 4 slots killing sticks in 1 and 3, and so only 2 of 4 sticks at once.

emoxam Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 14 Mar 2022 Status: Offline Points: 50	Post Options Post Reply Quote emoxam Report Post Thanks(0) Quote Reply Posted: 09 Apr 2022 at 9:14pm
	I tried to update bios to the same version, i reset bios few times - no luck.