I just installed a gig of RAM, and I'm not sure if its really being read to its max. I opened a gDesklets memory desklet and this is what it looks like:

So what does this mean?

I'm not familiar with gDesklets, but you can figure out how much RAM your computer sees by booting up into the BIOS. Note that there may be an option to set an "AGP Window" or reserve some memory for on-board graphics. These can reduce the amount of RAM available to the OS for regular use.

At a terminal, type top -bn1 and post the memory total. If it is not around 1024000 KB (1048576 KB to be more precisely) than you need to re-compile the kernel with high mem support. The kernel may take a few megabytes depending how much drivers are compiled as built-in.

Usually in Linux, on-board graphics defaults to 8 MB of shared memory unless you specify how much you give it to the X Windows System.

My kernel is supposed to support up to 4 gigs.

Are you sure. Distributions may or may not compile the kernel with highmem support and highmem support does not mean it can handle 4GB or more. The setting highmem support just mean it can handle over a gigabyte but not 4 GB. I specifically told you to post the results that top shows. top is meant to use with Linux. gDesklets may be written by someone that does not understand how memory in Linux is laid out. Probably the first number is free memory and the last two is cache and buffer. With out the headers for each value what gDesklets print outs, there is no way of telling. This is the reason why I suggest using top.

Another way is typing "zcat /proc/config.gz | grep CONFIG_HIGHMEM". If the file /proc/config.gz is not there, do not run the line because it will not work.

Is this what you need to see?