HP F8 Architecture Technology Brief
HP F8 Architecture
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Specifically, the Profusion 8-way architecture has a bus bandwidth of 800 MB/s for the
dedicated processor and I/O buses. The F8 architecture is capable of a bandwidth that is
four times greater: 3.2 gigabytes per second (GB/s) for each processor bus and for the I/O
subsystem (Figure 1).
Figure 1. Bandwidth comparison between Profusion and F8 architectures
The Profusion architecture ensures fast access to memory by using an aggregate memory
bandwidth of 1.6 GB/s. This is enough to balance the maximum bandwidth of the two
processor buses in the Profusion architecture. HP’s F8 architecture ensures even faster
memory access by using an aggregate memory bandwidth of 8.5 GB/s, which is
33 percent greater than the bandwidth of the two Xeon MP processor buses combined, and
more than five times the Profusion memory bandwidth.
In the F8 architecture, the total inputs to memory from the two processor buses and the I/O
bus provide a cumulative maximum of 9.6 GB/s. The bandwidth to memory is 8.5 GB/s.
Thus, the ratio of total inputs to memory to available memory bandwidth (8.5:9.6)
approaches an ideal one-to-one ratio, ensuring good scalability for the 8-way
multiprocessing system (Table 1).
Table 1. Comparison of bandwidth ratios for the Profusion and F8 architectures
architecture memory
bandwidth
processor buses + I/O bus bandwidth
(P1 + P2 + I/O)
ratio of
memory : processor + I/O
Profusion 1.6 GB/s 2.4 GB/s 1.6 : 2.4 (0.67)
F8 8.5 GB/s 9.6 GB/s 8.5 : 9.6 (0.89)
Profusion
Chipset
800 MB/s
800 MB/s
800 MB/s
Compaq F8
Compaq F8
Chipset
Chipset
3.2 GB/s
3.2 GB/s
>
5
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Aggregate
Memory Bandwidth:
8.5 GB/s
to Memory...
Processor Processor
Processor
Processor
3.2 GB/s
to I/O...
to I/O...
to Memory...
Aggregate
Memory Bandwidth:
1.6 GB/s
4
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Profusion
Chipset
800 MB/s
800 MB/s
800 MB/s
Compaq F8
Compaq F8
Chipset
Chipset
3.2 GB/s
3.2 GB/s
>
5
X
M
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m
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B
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Aggregate
Memory Bandwidth:
8.5 GB/s
to Memory...
Processor Processor
Processor
Processor
3.2 GB/s
to I/O...
to I/O...
to Memory...
Aggregate
Memory Bandwidth:
1.6 GB/s
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