Memory (main system), Bit computing – Toshiba Satellite C640 User Manual
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User’s Manual
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Satellite C600/C640/C645/C600D/C640D/C645D, Satellite Pro C600/C640/C600D/C640D
Under some conditions, your computer product may automatically shut-
down. This is a normal protective feature designed to reduce the risk of lost
data or damage to the product when used outside recommended
conditions. To avoid risk of lost data, always make back-up copies of data
by periodically storing it on an external storage medium. For optimum
performance, use your computer product only under recommended
conditions. Read additional restrictions in your product documentation.
Contact TOSHIBA technical service and support, refer to
section in Chapter 8,
64-Bit Computing
64-bit processors are designed to take advantage of 32 and 64 bit
computing.
64-bit computing requires that the following hardware and software
requirements are met:
■
64-bit Operating System
■
64-bit CPU, Chipset and BIOS (Basic Input/Output System)
■
64-bit Device drivers
■
64-bit applications
Certain device drivers and/or applications may not be compatible with a
64-bit CPU and therefore may not function properly.
Memory (Main System)
Part of the main system memory may be used by the graphics system for
main system memory available for other computing activities. The amount
of main system memory allocated to support graphics may vary depending
on the graphics system, applications utilized, system memory size and
other factors.
If your computer is configured with more than 3 GB memory, 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.
Computers configured with a 64-bit operating system can address 4 GB or
more of system memory.