computer wont see extra memory

[Zelores]

Im pretty sure this question gets asked all the time.... anyways. i recently bought a 1gb stick. Now i have 3gb (2x 1gb and 2x 512mb). The two 1gn are in dual channel as well as the 512 sticks. Right on the board says DIMM 1 and 3 are side by side and the same for 2 and 4. My computer and windows won't detect the 3rd gb but cpuz does. I have updated my bios to the most recent but no luck. I checked the manual but no luck. Im out of ideas. Anyone know whats the issue is? I have a machspeed mk8-939a. with a AMD Athlon 3000+.

thanks

i should also add that when i take both of the 512sticks out, it stays at 2gb. I heard that other hardware like the video card can take some of the physical memory.

[Zelores]

correction. its not an athlon, its a sempron

[compdoc]

make sure all the RAM is the same speed and they should be installed in pairs. for example both 1GB sticks should be in the blue slots and the 512MB sticks should be in the white slots. so it would be

1GB, 512MB and 1GB, 512MB
blu, wht and blu, wht

does this make since. is this how you have it.

[Zelores]

That is what I was doing. I figured it out why it wasn't working though. One of the sticks was bad. so i need to get another 512 stick. the strange thing is i left the good 512 in and when it was place in one slot. the computer said 1.4gb. i place it in the other slot the computer went back to 2gb. shouldn't it be 2.5gb?

[compdoc]

there could be a few reasons why it's like that. it could just be how the motherboard was designed or maybe you might have more than just one bad RAM stick or the slots could be faulty.

all you can do is just troubleshoot till you find it. you can also run memtest86 to test the memory although I don't fully trust memtest86, but I haven't found a better free software for that yet.