I am a graphics/video type of guy person thingy

I have installed 4 gigs of memory but Photoshop only recognizes a little less than 2 gigs. That exact amount amount of memory that PhotoShop says is available is "1760MB". However the "View system information" option under the "My Computer" window says that I have "3.50 GB of RAM" (I was told that my motherborad would not recognize all 4 gig so...what you gonna do). But I would like to at least be able to use the 3.5 gig that my system recognizes in Adobe Photshop.
I run my own graphics/video business and I need Adobe Photoshop to perform at its top potential for the work I do. Can anyone advise me on what to do to get Photoshop to run faster. I may be willing to design some free business cards (see samples of my work at www.studioeverything.com) for the awesome, intelligent, wise, effective, kind and super (please include every other nice word that can be thought of here) person who can help me.
Any takers on my offer? Would love to hear from you!
Thanks ALL!!!!

Eric