I just doubled the RAM on my new AMD 64 FX-4000 computer from 2 to 4gb, which MSI states that 4gb is the max for the K8N Neo4 Platinum/SLI motherboard. But in XP My Computer\ Properties the RAM reads only 3.25gb. When there were only 2 DIMMs (1gb each) it read 2gb, as it should.
All four of the DIMM's are exactly the same part number - CorsairVS1GB400C3.
Any ideas?
George:

When you start your computer does the Power On Self-Test (POST), which is the black display with white characters prior to the Windows XP LOGO, count the memory all the way up to 4 GB?

I pressed "Del" because everything flashes by so quickly so I hope this info is what you're looking for:

CPU type AMT Athlon 64 4000+
Bios Ver W7100NMS V3
System Memory = 3407872K
Total Memory = 3407872K
Yep, 3407872K = 3.25 GBDo you have an onboard Graphics card? i used to **shudders**. It used my ram as its memory and drained itCan you pull one of the new modules and get it to read 3Gb? Then swap it for the other new module and see if that reads 3Gb?

Quick way to see if one is faulty.Late yesterday I downloaded MSI live update software from the MSI website. There was a BIOS update & some system analysis’s software.
The BIOS update didn't change the RAM reading, but WMIinfo provided a great deal of system info.
Under "Memory" it list all four DIMMs like this:

Name : PHYSICAL Memory
Memory Capacity : 1024MB
Memory BankLabel : Bank0/1
Memory TotalWidth : 64 Bits
DataWidth : 64 Bits
Memory DeviceLocator : A0
Memory Type : Unknown

Name : Physical Memory
Memory Capacity : 1024MB
Memory BankLabel : Bank2/3
Memory TotalWidth : 64 Bits
DataWidth : 64 Bits
Memory DeviceLocator : A1
Memory Type : Unknown

Name : Physical Memory
Memory Capacity : 1024MB
Memory BankLabel : Bank4/5
Memory TotalWidth : 64 Bits
DataWidth : 64 Bits
Memory DeviceLocator : A2
Memory Type : Unknown

Name : Physical Memory
Memory Capacity : 1024MB
Memory BankLabel : Bank6/7
Memory TotalWidth : 64 Bits
DataWidth : 64 Bits
Memory DeviceLocator : A3
Memory Type : Unknown

I'm not a computer expert but it seems to recognize the four DIMMs as 1024MB each.

Kablam & Mac,
Here's the Video card info. It's a separate card, not onboard:

Name : MSI MS-StarForce GeForce 6800 GT (NVIDIA GeForce 6800 Series GPU)
Display Availability : Running/Full Power
Video Mode : 1280 x 960 x 4294967296 colors
Adapter DAC Type : Integrated RAMDAC
Current Horizontal Resolution : 1280 Pixels
Current Vertical Resolution : 960 Pixels
Current Number Of Colors : 4294967296
Adapter RAM : 256 MB
Current Refresh Rate : 60 Hertz
Video Processor : GeForce 6800 GT
Inf Filename : oem7.inf
Driver Version : 6.14.10.7122
Monochrome : false
Installed Display Drivers : nv4_disp.dll
Status : OK

As far as removing a DIMM to see if it drops to 3gb, MSI website warns against doing 3 chips; at least this is how I'm interrupting it. Here's a link to the MSI motherboard.
http://www.msicomputer.com/product/p_spec.asp?model=K8N_Neo4_Platinum/SLI&class=mb

About midways they describe memory.
I appreciate all of your responses & all further advice.
George
Yes, you are right about three modules. Sorry. OK then pull the two new ones, then pull one of the old ones. See if it is running OK on the one module.

Then put one of the new modules in as a second module and see if it will show 2Gb.

Then swap that one for the other new module and see if that will read 2Gb. Then you know that all four are working.

(You could pull all four and put the two new ones in, in place of the old ones, to see if together they read 2Gb as well.)

You read the warning about green and purple slots and which ones to use first.

Did you do all of the checks in BIOS and so on as recommended?George Ross..... This is from the blurb on your mobo ......read the very last item.........according to that ....you do have the 4 gb ........and things appear to be fine .

Dual-channel DDR works ONLY in the 3 combinations listed in the table shown above.
• Please select the identical memory modules to install on the dual channel, and DO NOT install three memory modules on three DIMMs, or it may cause some FAILURES.
• Always insert the memory modules into the GREEN slots first, and it is strongly recommended not to insert the memory modules into the PURPLE slots while the GREEN slots are left empty.  
• This mainboard DO NOT support the memory module installed with more than 18 pieces of IC (integrated circuit).  
• The Maximum memory speed decreases when the following two memory combination is selected:
- Each channel is installed with two double-sided memory module
- Both DIMM1 and DIMM3 are installed with double-sided memory module  
• Due to the South Bridge resource deployment, the system density will only be detected up to 3+ GB (not full 4GB) when each DIMM is installed with an 1GB memory module  

dl65  
"Due to the South Bridge resource deployment, the system density will only be detected up to 3+ GB (not full 4GB) when each DIMM is installed with a 1GB memory module."

Well spotted dl65, and to think that I only bought new reading glasses two days ago.

Now where did I put them, Thanks, dl65!
Well...I had my glasses on but didn't see that!
And thanks everyone for their help.
GeorgeThanks George, dl65 is sharp eyed all right, but just as well to know that all modules are fully operational.

hi i RECENTLY built a computer for a friend, i turned it on the CPU fan comes on the drives open, the HDD is working, and the computer is producing heat as normal but the screen automatically goes of when the computer goes on, and no bootup screen appears, obviously, this is the same for many screens, been building computers for a long time never seen this happen before! please help Please start a new thread.