Table 2–1 HBM Configurations
Pseudo
Channel
Density in
Gbit
Pseudo Channel Configuration
Row x Col x Bank Address Bits
Pseudo
Channel
Width
(bits)
Burst
Length
Stack Size
(16 Pseudo
Channels) in
GB
Total
Frame
Buffer
Size (2
Stacks) in
GB
4 14 x 5 x 5 64 4 8 16
2.1.2 Memory Aperture Size
The memory-aperture size can be set up through either pin straps for designs that do
not have dedicated ROM for the video BIOS, or ROM straps for designs that have
dedicated ROM. Refer to the descriptions of the ROM_CONFIG[2:0] and
MEM_AP_SIZE [2:0] straps in Pin-based Straps (p. 37) for more information.
"Vega 10" requires dedicated ROM for video BIOS. Therefore, memory aperture size
is set by ROM straps.
The memory aperture defines the address range that the CPU can access. The
memory-aperture size assigned to the GPU by the system BIOS is different from the
physical-memory size that the AMD display driver reports to the operating system
and control panel. It does not limit the GPU's ability to use the entire frame-buffer
memory at any time. Modern graphics and multimedia applications use drivers to
alter the frame-buffer contents—direct manipulation of the frame buffer by the CPU
is limited. Therefore, having a memory-aperture size that is smaller than the physical
frame-buffer size does not limit performance. The AMD display driver reports the
memory size based on the amount of physical VRAM installed on the card rather than
the memory-aperture size.
Due to memory-management constraints, the memory-aperture size should be the
same as the frame-buffer size for 64 MB, 128 MB, and 256 MB. For frame-buffer sizes
larger than 256 MB, the memory-aperture size should be 256 MB. For designs
requiring larger than 256 MB aperture size, consult with AMD.
4 Functional Overview
"Vega 10" Databook
56006_1.00
© 2017 Advanced Micro Devices, Inc.
AMD Confidential - Do not duplicate.
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