Posted 22 March 2010 - 02:52 AM
To add to Broni's comment, if you want to have full access to 8GB of memory, you'll have to install a 64-bit operating system.
As for the performance issue, it's hard to say, but the memory controller on some motherboards doesn't have sufficient current drive to operate a full memory complement at full speed, and will slow down. It may be that the configuration data is not being updated when the extra memory is removed. Some BIOS have an option to force an update, maybe called "Reset Configuration Data", or "Force ESCD Update". If you find this in the BIOS setup options, enabling it may restore the original memory speed.
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