It's most likely the on-board graphic card which is utilizing
the "missing" memory, as mayi has mentioned. Here's some
calculations to support this.
2 GB = 2048 MB
2048.00 - 1789.56 = 258.44
which is kinda close to the 256 MB of shared memory for the graphic
card. Mayi may have an idea about the remaining 2.44 MB, I
guess.
The Aspire 5050-5827 reviewed here was configured as follows:
Processor: AMD Turion64 x2 TL-50 (1.6 GHz, 512 KB L2 cache total,
256 KB on each core)
RAM: 1 GB 533 MHz DDR2 RAM (2 x 512 MB)
Hard Drive: 80 GB Hitachi 5400 RPM HD
Screen: 14.1-inch WXGA Acer CrystalBrite screen
Gaphics: ATI Radeon Xpress 1100 integrated graphics
(64-256mb shared memory)
Optical Drive: Dual layer DVD +/- RW combo
OS: Windows Media Center Edition 2005
Wireless: Atheros Wireless 802.11 b/g with Signalup high efficiency
antennae
Battery: 44.6 W 4000 mAh Li-ion battery (6-cell) with a rated 2.5
hrs battery life
From http://www.notebookreview.com/default.asp?newsID=3609.