12gb of ram installed, only see's 4gb or 2gb

[PhLoBuS]

So I put together a new computer:
Asus Rampage III Formula mobo
nVidia GeForce GTX 470
Velociraptor HD
i7-950
Corsair XMS 3 (12gb) DDR3 1333 triple-channel
Windows Vista Premium

Now sometimes it recognizes all of the ram, sometimes 4gb, sometimes 2gb. I go to my computer and right-click and go to properties to view this.

I have flashed the bios to the newest version and still the same issue. I ran a memtest in DOS and all sticks passed. I currently have 8gb plugged in instead of 12gb's. Still only see's 2gb. Who knows it may see 4gb tomorrow. It seems pretty random.

I just reformatted a few days ago to see if that would do anything but it didn't.

Any ideas let me know! Thanks -Matt

 

[jaquith]

Welcome to Tom's Forums!

10GB loss beats the 8GB record I've seen.

Q - Is your Vista 32-bit or 64-bit?
Q - What exact XMS do you have installed? CMX12GX3M3A2000C9 or CMX12GX3M3A1333C9...

R3F {R3E} http://www2.corsair.com/configurator/product_results.aspx?id=1493037

 

[PhLoBuS]

Windows 7 Ultimate 64-bit

2x CORSAIR XMS3 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Triple Channel Kit Desktop Memory Model TR3X6G1333C9

 

[jaquith]

They're not XMP, so you'll need to manually set the RAM. If the following fails then BIOS 0505 might be an option, but first things first. I assume that the 2 sets are NOT randomly mixed together; Set 1 = A1/B1/C1 and Set 2 = A2/B2/C2.

1333 MHz 9-9-9-24-2T @ 1.5v

BIOS:
Load Defaults **
** if you changed CPU Fan {e.g. 100% Corsair H50/H70} or IDE-> ACHI then change from defaults.
AI Overclocker Tuner -> Auto
DRAM Frequency -> DDR3-1333 MHz
DRAM Timing Control {enter}
-> 9-9-9-24
Timing Mode 1N -> 2N
--
* DRAM Bus Voltage -> 1.5v~1.6v
* QPI/DRAM Voltage -> 1.20~1.35v in 0.05 increments

* {this is sometimes needed for 6 DIMM} if there's not enough voltage the DIMMs will be under powered and hence the irregularities.

Failure, pull Set 2 A2/B2/C2; remove black slots -> see if 6GB shows-up. Next, swap Set 1 for Set 2 in the Red slots -> see if 6GB shows-up.

Post those results. If BOTH single sets work then it's a Voltage issue.

Failure, use the settings above, create a Memstest CD/DVD {ISO/zip} http://www.memtest.org/

 

[PhLoBuS]

Yes I am using a Corsair H70, forgot to mention that.

 

[jaquith]

Then I assume that you set the fan @ 100% a/k/a pump.

BIOS:
CPU Q-Fan Control -> Enabled
CPU Fan Profile -> Turbo

Q - Did the other BIOS settings correct the problem?

 

[PhLoBuS]

About to try now. Let you know!

 

[PhLoBuS]

It worked, computer recognizes all ram installed!

 

[jaquith]

Cool Glad to hear!

Use the Fan settings for the H70, you want the pump with 100% power + runs cooler.

 

[PhLoBuS]

Alright! Thanks a lot for the help.

What if I overclock my CPU, it usually changes some of the RAM parameters. Will I be ok?

 

[jaquith]

If you used XMP and didn't manually set the voltages then yes, but it's always a good idea to double check DRAM Frequencies. The manual settings lock-in the values which is one of the reasons I prefer to manually set all the RAM values.

 

[PhLoBuS]

Well I just got home from work and check it... its reading 2gb of ram

 

[jaquith]

Sorry to hear, 50/50 {bad stick/voltage} per above. Just 'in case' use Isopropyl alcohol and dampen the RAM contacts then place in DIMM slots clean and repeat X2 per DIMM, allow to dry ~10 minutes. In the machining process oils are used so not to tear the DIMM contacts while Mfg.

My assumption is the RAM is good, but the contacts/voltage isn't Dialed-in yet.

Failure:
1: Try the upper values (1.55+v/1.30+v)
* DRAM Bus Voltage -> 1.5v~1.6v
* QPI/DRAM Voltage -> 1.20~1.35v in 0.05 increments

FULLY using ALL DIMM slots takes more power and all too often ALL the DIMM slots do not 'get' adequate power, therefore requiring a slight over voltage. None of the voltages I'm posting are 'high' and I am on the conservative end. RAM can run ±0.2v~±0.3 Volts and is considered within normal ranges. Think of it with 6 filled slots as having a runt of the litter not getting enough 'juice.' Too much or too little - neither is good, you need to keep 'tweaking'.

Some people might recommend, but I know Volts = Heat.
* DRAM Bus Voltage -> 1.6v+
* QPI/DRAM Voltage -> 1.3~1.4v in 0.05 increments

2: Failure with upper values.
Failure, use the settings above, create a Memstest CD/DVD {ISO/zip} http://www.memtest.org/

I'll keep up with you in this post.