Toshiba L550 User Manual page 23

Memory
Slots
For users of a 32-bit version of Windows: If your computer is configured
with two 2 GB memory modules or more, the memory might be displayed
as approximately 3 GB only (depending on the computer's hardware
specifications).
This is correct because the operating system usually displays the available
memory instead of the physical memory (RAM) built into the computer.
Various system components (like the video adapter's GPU and PCI
devices like Wireless LAN, etc.) require their own memory space. Since a
32-bit operating system cannot address more than 4 GB of memory these
system resources overlap the physical memory. It is a technical limitation
that the overlapped memory is not available to the operating system.
Even though some tools might display the actual physical memory built
into your computer, the memory available to the operating system will still
be approximately 3 GB only.
Maximum size of memory can be installed on Mobile Intel
Express Chipset models is 4GB.
PC2-6400 memory module works as PC2-5300 speed on AMD Athlon/
Sempron™ Processor.
Video RAM
User's Manual
PC2-6400 1 GB, 2 GB or 4 GB memory modules
can be installed in the two memory slots of below
models:
Maximum system memory size and speed are
depending on the model you purchased.
Video RAM depends on the model you
purchased.
Mobile Intel ® GM45 Express Chipset model/
Mobile Intel ® GL40 Express Chipset model:
Video RAM capacity shares with main memory,
and the proportion depends on Dynamic Video
Memory Technology.
Mobile Intel ® GM45 Express Chipset model in
graphic chip by ATI Mobility Radeon™ HD 4570:
External 256/512MB
AMD M780G Chipset model/ AMD M780V
Chipset model: Video RAM capacity shares with
main memory, and the proportion depends on
ATI HyperMemory™.
AMD M780G Chipset model in graphic chip by
ATI Mobility Radeon™ HD 4570:
External 256/512MB
L550/L550D/L555/L555D
® GL40
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