P9x79pro showing only half memory

Assuming the RAM is set in the BIOS - AI Overclock Tuner -> XMP and it fails then you can 'try' to increase both the VTT & VCCSA Voltage -> 1.10v (failure) then 1.20v max.

Otherwise, I'd love to Sugar Coat this, but it's time for an RMA. If you purchased it from e.g. NewEgg they offer 'Expedited RMA' or if older than >30 days then you can try to request ASUS's 'Cross Ship RMA', otherwise it's (3) weeks total time turn around.

Missing or dead DIMM slots is a rampant problem on 8xDIMM ASUS X79 MOBO's.

asus dram spd info..it says 2 dimms abnormal..... swapped ram around get same info...


no more mouse,keyboard, or system lockup, but only reading half memory..

man alot of money for hardware,,should not fail like this,,ive always bought gaming system prebuilt, 2 systems from alienware,,still got one. this is my first home built system..

kind of figured maybe a bad ram slot,,,board is new,,1 week old.. it worked for a few days .
amazon sending a new one tomorrow, 2 day shipping, no charge. just have to send old one back within 30 days.... amazon is the way to go..easy returns no questions asked.....

thanks for info..

Good luck, and let me know how it turns out for you.

so i removed 2 dimms, 2x4gig from the 2 slots that say abnormal...i only have 2 dimms in now,,but they are in 2 slots that are not recommended when using only 2 slots, per manual, seems to be running fine,,
shows 8 gigs memory, but running dual channel,,swapped the dimms around, still only 2 dimms in non recommened slots, but still running fine ,,i guess those 2 slots are bad.......B1 and D1 slots say abnormal...
so i ruled out the dimms,,got to be mobo..... new one coming today..

Hmm...Otherwise, I'd love to Sugar Coat...

This problem has been plaguing many of the ASUS 8xDIMM MOBO's, IMO as first stated RMA. However, again I assume that you tried the VTT & VCCSA (see above).

Q - What exact RAM? (provide a link)
Q - What exact changes in the BIOS? (above (F5) Defaults)

Kingston Technology HyperX 16 GB Kit (4x4 GB Modules) 16 Quad Channel Kit 1600 (PC3 12800) 240-Pin DDR3 SDRAM KHX1600C9D3K4/16GX

dram voltage channel a/b/c/d/.........1.65 volts
vttddr voltage........... auto
vccsa..........................auto



thanks,, trying to learn

dram voltage channel a/b/c/d/.........1.65 volts
vttddr voltage........... auto ; change to 1.10v
vccsa..........................auto ; change to 1.10v

changed vttddr voltages to 1.1

vccsa loadline calibration..it was auto...i put it on high...auto/reg/high/extreme
vccsa current capability i put it on 110%...................100/110/120/130%

i saw a cpu vccsa ??

put all 4 dimms back in rebooted,, maybe they needed more voltage ?? time will tell... ill let ya know

thanks!! 4 your help..

VCCSA LLC is only necessary if OC'ing. IF the 1.10v didn't help then try 1.20v but nothing higher, 1.20v is the max safe voltages.

system ran for about one hr. memory error,,,took 2 dimms out, from suspected bad slots,,
will see how long it runs with 2 dimms......

it was overclocked alittle using asus ai suite.. system rebooted,, said oc/ing failed... got same settings with just 2 dimms,,,,time will tell,,new mobo just got here........

thanks..

IMO - don't use the AI Overclocking Suite (i.e. uninstall), and especially not if it and you are changing the BIOS. Even if that App isn't in your 'face' it is running 100% of the time in the background.

Try setting the RAM 100% manually:
AI Overclock Tuner -> Manual
DRAM Frequency -> (RATED) e.g DDR3-1600
CAS Timings -> per (RATED) e.g. 9-9-9-24-2N (CAS-TRCD-TRP-TRAS-COMMAND RATE)
DRAM Voltage -> per (RATED) e.g. 1.65v
VTT & VCCSA Voltage -> 1.10v~1.20v ; note >1.35v has been proven to degrade the CPU!

Keep in mind, unfortunately there have been many cases of bad DIMM slots on the X79; quickest solution Expedited RMA from Reseller <30 days or ASUS's 'Cross-Ship' if available in stock otherwise count on 21+ days total time for conventional RMA...

thanks for all your help...it was a bad board, 2 bad, intermittent slots,,
replaced mobo yesterday afternoon,,system has been running ever since... man its lighting fast.
time to start loading a few games... system is all updated,,,

thanks again!!!!!!! have a great day.........

Intel® Core™ i7-3930K
HyperX 16 GB Kit (4x4 GB Modules) 16 Quad Channel Kit 1600
ASUS P9X79 Pro MOBO
Razer BlackWidow Ultimate Mechanical Gaming Keyboard
EVGA GeForce GTX 580 3072 MB GDDR5 PCB
Corsair Professional Series Gold 850-Watt 80 Plus Gold Certified High-Performance Power Supply -
Cooler Master HAF ATX Mid Tower Case, RC-922M-KKN1-GP (Black) extra red led side fan
Thermaltake CLP0564 Frio Dual 120mm Universal CPU Cooler
Plextor PX-L890SA-26 24X SATA Super Multi DVD+/-RW Internal Drive
Western Digital Caviar Black 1 TB SATA III 7200 RPM 64 MB Cache Internal
boot drive...OCZ Vertex 3 120GB SATA 6Gb/s VTX3-25SAT3-120G 2.5" Solid State Drive (SSD)
Windows 7 Professional SP1 64bit (Full) System

No surprise here, and I'm glad it's working well!!!  

Further, IMO run something like AIDA64 with all option selected for 24 hours. If a MOBO is going to be a problem anytime soon then you might as well discover it ASAP then in a middle of a project/game.

My Saberthooth was fine for a couple days then rapidly deteriorated and had to be exchanged.