Example 3 - HP d325 MT Introduction Manual

Example 3

In this example (shown in Figure 3), the end-user is deploying mismatched DIMMs. There is an
alternative graphics driver.
Note
An alternative graphics driver may behave differently than an HP driver if
memory is mismatched, as in this example.
Figure 3: Dual-channel memory with mismatched DIMMS, alternative graphics driver.
The BIOS maps upper memory to be 64 bits wide, lower memory to be 128 bits wide.
The BIOS maps the specified graphics memory allocation to the top of the memory space (part of the
larger DIMM). The allocation is 64 bits wide.
An alternative driver may automatically re-map the graphics allocation to the faster 128-bit memory
space to optimize graphics performance. However, the space originally allocated by the BIOS for
integrated graphics is still hidden from the operating system and cannot be used, reducing the amount
of memory available for other applications.
In addition, boot time may increase substantially as data from upper memory are copied to the 128-
bit space.
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