OS X Mavericks :: IMac Running Slower Since Update

Since upgrading to Mavericks my Mac has been running pretty slow. I run Logic Pro 9 and Ableton 8 music programs on my computer quite often and that's where i notice significant lag. I understand those are heavy programs, but even when Safari is open and I try to open Finder there is lag time before the window actually opens. When I restart my computer, it runs a little better, but as soon as I begin to open other programs, the lag begins and will continue even after I close them.

I upgraded from Snow Leopard and never had any issues- it ran extremely smooth under the most stressful conditions with all the current memory and hard drive space, cpu, etc. I

EtreCheck version: 1.9.15 (52)Report generated August 26, 2014 at 12:37:45 PM CDT Hardware Information: ?  iMac (21.5-inch, Late 2009) (Verified)  iMac - model: iMac10,1  1 3.06 GHz Intel Core 2 Duo CPU: 2 cores  4 GB RAM Video Information: ?  NVIDIA GeForce 9400 - VRAM: 256 MB  iMac 1920 x
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Info:
iMac (21.5-inch Late 2009), OS X Mavericks (10.9.4)