E6520: 1600x900 vs. 1920x1080 Display options?

Not really...it will become fuzzy at a lower than native resolution. Personally, that would drive me nuts...

 

The reason the FHD+ (1920x1080) isnt as popular as most are probably keeping them. 1600x900 is great for smaller laptops, but in a 15.6in laptop its too low. But like others have if you get the higher resolution you can always turn it down.

 

So a FHD (1920x1080) is not so usable as HD+ (1600x900) ?

 

It's more usable, but potentially less comfortable because of the higher DPI.

15.6" 1600x900 is actually pretty close in physical height to 14.1" 1440x900, and I'm pretty happy with the 1440x900 screen in my D620/D630/E6400/E6410. I've been wary of high resolutions after making a terrible choice of getting the optional 15.4" 1920x1200 screen for my M70, which caused plenty of eye fatigue.

If small text size is any bit of a concern for you, go with the 1600x900.

 

The FHD(1920x1080) resolution is not so readable in the office , like HD+(1600x900)...

 

With 15.6 1920x1080, just set your display text size at 120dpi (125%), also set the Windows XP scaling on and you'll be fine. This is a very common setting on moderately high dpi screen (such as the Vaio Z). This has been a non issue for years.
See the new IPad to see how a high dpi screen can be pleasing. Nice to see that Apple is forcing the issue to be fully dealt even for very high dpi setting such as Retina.

 

There's a big difference between Windows and a controlled environment like Apple devices. Many Windows applications will not look nice with DPI scaling, and icons often have to be stretched because higher resolution versions are not available. Furthermore, even Windows itself does not play nice (ie. spacing for icons and taskbar don't scale proportionately, so there are gaps and wasted space), so DPI scaling is more like a last-ditch option.

In every single case I've seen so far, there is really nothing that can be done other than getting a different laptop, because users are rarely satisfied with DPI scaling and downgrading the LCD is cost-prohibitive.

 

I am just saying that for many people, setting the dpi at 120dpi is perfectly acceptable. This is how all Sony Vaio Z (13.3 inch 1600x900 or 1920x1080) have been set for ages and it is well accepted by their users (I have a Z1 1600x900 these days). Of course it is a matter of personal preference. There is really no scaling involved for most apps, it is just that you use more pixels per point. Because the increase is modest (20% or so), the possible side effects are negligible.
In Windows 7, there is another setting for compatibility scaling which determine whether unaware apps are scaled (the result is either a a blurry display, I don't like it or tiny characters for some apps such as some Adobe apps). This is called 'Use Windows XP style DPI scaling' in the custom DPI Setting panel. I have found for moderately high dpi screen (the one for which setting the dpi at 120dpi will result in legible characters) the end result is OK.
Setting dpi at any value other than 100% has gotten a bad press which is not justified imo. I have used 125% for years without major inconvenience and with the added benefit of much nicer text.