[Memory] Upgrading ram issue.

[bossuwe]

Currently I have 2x1GB PQI DDR2 800MHz and I decided to purchase another 2x1 GB GSkill Memory for upgrade. When i try to use all the 4GB sticks at once, I could not boot up my comp. The maximum that i can use is 3GB and it runs perfectly. I have been having problems with 4GB rams running together. I already tested the memory rams 1 by 1 and they are perfect. How do i solve this problem?

 

[Mondoman]

Some MBs have trouble running 4 DIMMs at a time; if this is your problem, you might try increasing the memory voltage (sometimes called Vdimm) by 0.1V or so.
However, another likely possibility is that your MB won't work properly with 4GB installed, because of issues with mapping various hardware to memory addresses just under the 4GB mark. A number of MBs that in theory take up to 4GB seem to be unstable at best and not booting at worst when 4GB are installed.