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Motherboard & Windows only recognize 2GB RAM when 4GB installed..why ?

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May 11, 2008 10:07:55 PM

Hey guys,

In my current setup, Im using a DFI LANPARTY UT nF4 SLI-DR Expert motherboard, with 2x 2gb Kingston Hyper X PC3200 (DDR400) dual-channel RAM. I know Vista 32-bit doesn't support 4gb of RAM. Would it round down to 3GB, or just ignore the second stick and only recognize 2GB?

My question is, should my motherboard (BIOS) be recognizing 4GB of RAM when I boot the system? When the system boots up it only shows 2096MB of RAM installed.

Should I switch to Vista Ultimate 64-bit, 4gb of RAM showed up using XP Professional x64 or there is a problem with my motherboard, or is there a probelm with one of my sticks of RAM?

Thanks.
May 11, 2008 10:20:48 PM

Well you have a problem if your motherboard doesn't detect all the RAM in the BIOS. If XP x64 detected it then Vista x64 should as well. To check if one of the memory slots is bad on your motherboard, just try one stick of RAM in the system. Try this in each slot on your board. If all four memory slots work then download a copy of Memtest86 and try testing the memory, try this with both sticks of RAM in the system. Run the test for at least 5 passes of the complete series of tests. If you don't get any errors the memory should be fine. If you do get errors, then try it one stick at a time to find the bad one.

Here is where you can get Memtest from:

http://www.memtest.org/

Download the latest ISO version and burn it to a blank CD, its a bootable disk once burned make sure your BIOS is set to use your CD or DVD drive as the first bootable device. Just stick it in and start up your PC and it will start the program.
May 11, 2008 11:13:56 PM

Ok, I tried every configuration for installing the RAM. (1A,3B) (1B,3A) (2A,4B) (2B,4A). I also tried both sticks individually in each slot. The machine would not boot up with only on stick installed in either slots 3 or 4, with nothing installed in slots 1 or 2.

I'm using Kingston HyperX KHX3200AK2/2G PC3200 (DDR400) dual-channel RAM.

With only one 2GB stick of RAM installed in either slots 1 or 2, both the BIOS and Windows only recognized 1024MB. With boths sticks 4GB (2x2GB) of RAM installed in either slots 1,3 or 2,4 both the BIOS and Windows recognized 2096MB of RAM. The manufacturer recommends using slots 1 & 3 for PC3200 (DDR400) dual-channel RAM.

So what gives, why is only half of my RAM being recognized?
Related resources
a b } Memory
a b V Motherboard
May 12, 2008 12:20:59 AM

A 32 bit OS only has 4GB worth of address space. Ite's OTHER THAN RAM have to come first. And the more you have installed, the less will be left over for memory. So if you are running 2 x 512MB cards in SLI, for example, that's 1GB worth of address space taken from teh 4GB bucket. And that's not even counting the CMOS, any other PC1i devices, com ports, and the myriad of other items on your PC which must be addressed first. RAM gets what's left over.
May 12, 2008 1:26:42 AM

The is usually a "memory remap" feature in the BIOS, this got my 4gb detected in the bios
May 12, 2008 1:50:44 AM

This is direct from Kingstons site:
KHX3200AK2/2G 2GB 400MHz DDR Non-ECC CL2
(Kit of 2 - 1GB) 2-3-2-6-1 2.6V (Datasheet) BUY

You bought a kit of 2x1G that is why. Next time read closer before you buy. The first give away was prolly the price you paid, you probably really thought it was a bargain for 4G when infact it was the right price for 2G.

Theres nothing you can do but buy more ram to equal 4G. Then you might run into memory addressing problems, but that is not the case this time.


You musta been dreaming when xp64 showed 4G, because it didn't happen with the sticks you have.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

I dont think its even possible to get 400 ram in 2G modules. Your mobo is rated four 4G and has 4 slots so it was never made for 2G sticks even if it did exist.
Heres a link to your rams exact model number that you posted.
May 12, 2008 2:41:12 AM

LOL $471.00. Just as well say it dont exist. I could buid a decent PC for that price. Good ****.
a b V Motherboard
May 12, 2008 3:17:11 AM

lol! nice catch
May 12, 2008 4:28:20 AM

lol nice roadrunner... i didnt even realise OP was on about DDR not DDR2
May 12, 2008 1:17:05 PM

roadrunner197069 said:
LOL $471.00. Just as well say it dont exist. I could buid a decent PC for that price. Good ****.



I know, that is crazy. It makes it even worse because it is DDR. WTF?
May 15, 2008 8:00:39 PM

Sorry, I can see how I was misinterpreted. I meant I had 2 of the kits 2x (2x1GB), I should have listed it as 4x1gb.

After some more digging, I believe the problem is with the memory remapping feature. Does anyone know how to change it for the particular mobo?
May 15, 2008 9:11:52 PM

Scotteq said:
So if you are running 2 x 512MB cards in SLI, for example, that's 1GB worth of address space taken from teh 4GB bucket. And that's not even counting the CMOS, any other PC1i devices, com ports, and the myriad of other items on your PC which must be addressed first. RAM gets what's left over.


The gfxcard makers know about the shortage of address space. So when the VRAM grows so large, they tend not to map it all into the address space. CMOS and com ports don't live in the cpu's memory address space, even if they did, they don't take up much.
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