Photoshop :: Monitor Resolution And CS6 Magnification Level

I'm going to be purchasing a new PC computer system in the near future; which will be loaded with 64-bit Windows 8 or 8.1.  I'm presently using CS5 & CS6, both 64-bit versions, on existing computers that have Windows 7.My work is photography and I do a LOT of masking.  In order to see what I'm doing while creating masks, I typically use CS5/6 image magnifications of 300% & 400% with a monitor that has 1680x1050 resolution.  On another monitor with 1920x1080 resolution, I have to increase my working space magnification to 400% & 500% to get the same "view size" of my work.  That's because the "view size" decreases as the monitor resolution increases.  My main problem is that CS5/6 will not produce "smooth" images at a magnification over 500%; as the image is pixelated to a degree that I can't accurately cut a mask.  Therefore I need to do my work at magnifications of 500% or less, but I need a "view size" large enough so that I can comfortably see what I'm doing.
 
For my new system, I'm considering monitors with 2560 horiz resolution.  In order to maintain my on-screen "view size" of the 1680 & 1920 monitors, a 2560 monitor would probably force me to use CS magnifications in excess of 500%.
 
What can I do such that CS will produce "smooth" (non-pixelated) images at magnifications greater than 500%?  Or...what can I do to make the entire CS window appear larger; so the "view size" of the 2560 resolution monitor is comparable to a lower (1920, for example) resolution monitor?