Macbook Pro Core i5 Memory Issues

The nitty gritty:

My i5 with 4GB of memory is using more memory to perform the same tasks as my Core Duo. They are the same clock speed.

In general, my laptop is constantly setting at nearly zero free memory, in spite of no major memory consuming applications running.

My wired and active memory add up to more than the real memory being used according to Activity Monitor! I just added up all the real memory usage and got about 1800MB, but Activity Monitor reports 2480MB as wired or active.

3.67GB of 4GB is currently used.

I know that OS X and other Unix systems always have a lot of inactive memory, but my old Core Duo did not do this.

Now, there's all the numbers, and here's the rest:

My laptop feels SLOW. In spite of low CPU usage, it is grinding way too much, and I think it's from having to free memory constantly, because I never have any free memory.

The i5 feels slower than my Core Duo, and that's insane because it benches nearly 20% faster.

I've ran all sorts of hardware tests, repairs and maintenance tools.. to no effect. Have also done SMC/PMU and RPAM resets.

Is anyone else experiencing this?