This resolution is not the standard 4:3 aspect ratio but 5:4 (1.25:1 instead of 1.333:1). A standard 4:3 monitor using this resolution will have rectangular rather than square pixels, distorting the picture and causing circles to appear elliptical.
SXGA is the most common resolution on 17", 18" and 19" desktop LCD monitors. The majority of these monitors have a physical 5:4 aspect ratio, avoiding any distortion (e.g. the Samsung SyncMaster 172T, which measures 335 x 275 mm displayable).
Apple Computer referred to displays with this resolution as "two-page displays", because they could be used to display two A4 pages side-by-side at a resolution of 72 dots per inch.[citation needed] Sony manufactured a 17" CRT monitor with a 5:4 aspect ratio designed for this resolution. It was sold under the Apple brand name.
Any CRT that can run 1280x1024 can also run 1280 × 960, which has the standard 4:3 ratio. It's often a matter of tweaking or changing the video driver to be able to run this resolution, as some only offer 1280x1024. Displaying any 4:3 resolution on a 5:4 monitor, like a TFT with a native resolution of 1280x1024, will look stretched. But, on a TFT, displaying any other resolution than the native one is not a good idea anyway, as the image needs to be interpolated to fit in the fixed grid display.
A variation is SXGA+ which is 1400 × 1050 common on laptops since circa 2003.
There is much speculation on the origin of SXGA. Some believe its use began back in the mid-1980s, as an upgrade from XGA 1024×768. At the time, memory was extremely expensive. Using 1280×1024 at 8-bit color depth allowed 1.25 MiB of video RAM usage, fitting nicely with available RAM chip sizes.[1][2]
1280 pixels × 1024 pixels = 1,310,720 pixels
1,310,720 pixels × 8 bits/pixel = 10,485,760 bits
10,485,760 bits ÷ 8 bits/byte = 1,310,720 bytes = 1.25 MiB
