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I can't use more than 2GB of memory

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April 20, 2010 1:25:21 AM

I am having real difficulty getting my new PC to work properly - I bought an Asus M4A785TD-V Evo motherboard with 8GB RAM (4x 2gb Ocz DDR3 PC3 10666, PN OCZ3G13332G) plus a Sapphire Radeon HD5770 and a Phenom II X2 550 BE

At first I thought my PSU wasn't powerful enough because my system would BSOD and have random errors when I tried to run Windows 7...but after buying a new PSU I have found that's not the case.

If I run all 4 sticks of RAM (8GB) then Windows doesn't even manage to boot...I get the BSOD for a split second then it will restart. Now I can get the system to start with 2 sticks of RAM (4GB) but then if I start running games like COD4 it will play for a little while then the screen turns off and I have to physically turn the PC off. Finally if I boot the system with just one stick (2GB) everything seems to run fine, I can use Windows ok and I ran COD4 with no problems.

So why can I not seem to have more than 2GB ram in my system? Do I need to manually set anything in the BIOS, because it's all on auto at the moment which I would presume should make it all work ok! I have always built my own computer...but I don't really understand RAM timings or voltages or anything like that!

If someone could please help me I would be so grateful...I really want to play with my new toy! :) 

More about : 2gb memory

April 20, 2010 6:12:03 AM

Exact same thing happened to me when I built my i7-920 rig with 12GB of Patriot RAM (two 6GB kits). First, it ran OK, then a couple of days later only 10GB showed up in my memory gadget in Win7. The BIOS only showed 8GB I think. That's when the BSODs started. Process of elimination showed a bad stick of ram. I RMA'd the kit it came from, and a few days later I got a new kit from patriot and it's been cruisin' for a year. I think you have a bad stick.
April 20, 2010 6:14:26 AM

what Operating System you have .. win 7 or xp ... 32 bit or 64 bit OS
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April 20, 2010 8:38:43 AM

From what you described the problem seems to be related to the the RAM voltage. Look in your MoBo's manual for the voltage that is needed when you use 4 RAM modules and how to set it manually.
There can be another issue with your current MoBo's bios version that does not support 4 modules of the specific RAM that you bought.
April 20, 2010 8:47:20 AM

you are using a 64bit OS right?
April 20, 2010 11:03:49 AM

I have Win 7 64-bit.

I think the RAM is working ok because I have tried each stick individually and they all work fine, but as soon as I double them up or put all 4 sticks in is when I start having problems.

I thought it might be the voltage, on the RAM sticks it has written: 9-9-9 @ 1.7v, but I don't really know what i'm doing with RAM voltages in the BIOS...it says "Memory OverVoltage" and I can leave that on auto or add more voltage...but how do I know what it starts off on? Should I just start incrementing that each time until it becomes stable? I don't want to do anything wrong and mess up my RAM!
a b } Memory
April 20, 2010 4:13:48 PM

Your motherboard owners manual will tell you how to set the RAM values in the BIOS. The DDR3 standard voltage is 1.5v. If your RAM requires 1.7v then you need to raise the RAM voltage by .2v. You also need to manually set the RAM speed and timings in the BIOS. Again, your motherboard owners manual will tell you how to do it.
April 21, 2010 1:12:12 AM

I tried increasing the voltage to 1.7v, and it managed to get to the password screen...but then crashed. I have just loaded up CPU-Z with the 2GB in, and it's saying the CL, tRCD, & tRP are all at 7 clocks, and the tRAS is at 16 clocks. Should that be saying 9,9,9 and 20? Have I basically got my RAM overclocked at the moment which it can handle with 1 stick but not 4?

Sorry if I sound stupid...I have never had to fiddle with RAM timings before so it's all foreign to me!

And thanks for your guys help so far :) 
a b } Memory
April 21, 2010 6:36:24 AM

Yes, it looks like your timings are not set correctly. You should manually set the speed, timings, and voltage to their rated values in the BIOS.
April 21, 2010 11:15:40 AM

OK, so i've set this: CL 9, tRCD 9, tRP 9, tRAS 20 and the voltage to 1.7v - but it's still not working. One of the sticks doesn't work on it's own anymore, it crashes every time so I think that might be a dud. So I tried the other 3 sticks with those settings and it booted Windows, but then aero crashed and it all went a bit wobbly :) 

This is so frustrating as there doesn't seem to be a whole lot of information regarding RAM timings for my sticks...plus there are a ton of other settings that I haven't changed like tRTP, tRC, tWR, TRRD, tRWTTO and more...what on earth does all that mean and should I be taking those off auto?

I miss the old days when you could just shove memory in and go!
a b } Memory
April 21, 2010 2:46:50 PM

You only need to change the first four values for the RAM timings. The rest can stay on auto. Have you run Memtest86+ to test for RAM errors? It's possible you have more than one faulty stick of RAM.
April 22, 2010 1:50:06 AM

I think i'm finally starting to get to the bottom of this...I tried running Memtest86+ but it just kept crashing (it's still reporting the wrong processor, ram type and timings) so I used Windows Memory Diagnostic on each stick of ram individually, and 2 of the sticks reported errors.

So I have removed those 2 sticks and have the 2 supposedly working sticks in and so far so good. Hopefully my system is stable now!

I just have a couple more questions...in CPUID there are a few things I just want to check are correct - it says "DRAM Frequency 525.7 MHz", "FSB:D RAM 3:8", "Bank Cycle Time (tRC) 27 clocks" and "Command Rate 1T" are they all correct?
April 22, 2010 10:13:14 AM

I spoke too soon...I have run the Windows Memory Diagnostic on the 2 sticks together and that doesn't report any errors, but my system is unstable. If I load up any games it will crash, sometimes restarting the PC...and sometimes it will just crash whilst on the desktop - random things will report errors like windows security essentials, and windows update.

Is there still some settings I need to tweak to get this stable?
April 23, 2010 11:23:49 AM

It's solved! (I hope) I posted on the OCZ forums as well and an OCZ guy posted this to me:

Quote:
Lets go with the basics to ensure the other sticks are in fact bad.

Set the following manually in the BIOS:

Set VDD NB Overvoltage to {1.35 volts}
Set memory Clock Mode to {Manual}
Set memory Clock Value to {667 Mhz}

Set DRAM Timing Mode to {Both}
Set Memory Timings to CL 9-9-9-20 (TCL-TRCD-TRP-TRAS)
Set Memory Overvoltage to {1.7 volts}
Set Memory hole Remappng to {Enabled}
Set DCT Unganged Mode to {Always}

Try running Memtest86+ v4.0 ( www.memtest.org ) using the memory in pairs and individually to identify the bad sticks in question.


So I set those values and the system was much more stable, but it still crashed...after running Memtest86+ (v4 not v3.5 which didn't work) I discovered that 2 sticks were bad. I've now got the 2 working sticks in and it's all running great, I can run anything maxed out :D 

If I get any more instability I will post back on here, but otherwise if you are just looking here because you have an Asus board and that OCZ ram those settings above are what you need to get it all working!

Thanks for all your guys help on here...i've learnt a lot about RAM timings over the last couple of weeks!
!