Figures

Apollo Guidance Computer Block II processor: recorded figures
Metric Value Evidence Basis Method Source
Clock frequency cpu 2.048 MHz Confirmed Vendor-rated Nominal clock Stated by the vendor Master oscillator rate, stated by the report as 2.048 megapulses per second.
Memory cycle time cpu 11.7 µs Confirmed Vendor-rated Nominal cycle time Stated by the vendor Twelve time pulses of 0.977 µs. Fixed and erasable memory share one cycle time. The report gives 11.7 µs both in table I and in the running text. Twelve pulses of 0.977 µs would be 11.724 µs; the rounded figure the report states is the one recorded.
Instruction execution time cpu 23.4 µs Confirmed Vendor-rated Addition instruction Stated by the vendor Single-precision addition: two 11.7 µs memory cycles.
Instruction execution time cpu 46.8 µs Confirmed Vendor-rated Multiplication instruction Stated by the vendor Four 11.7 µs memory cycles. Block I took 117 µs for the same operation. Not comparable with the addition time: a different instruction is a different comparability group, and the ratio between them describes this machine's order code rather than its speed.
2 documented absences
Apollo Guidance Computer Block II processor: recorded figures: documented absences
Metric Value Evidence Basis Method Source
Peak FP32 rate cpu not applicable The AGC has no floating-point hardware. Its arithmetic unit is a one's-complement fixed-point adder with shifting gates, so there is no rate to state — the question does not apply. Not stated Vendor-rated Theoretical peak Stated by the vendor
Peak FP64 rate cpu not applicable No floating-point hardware. The double-precision instructions in the Block II order code operate on pairs of 15 bit fixed-point words, which is not double-precision floating point. Not stated Vendor-rated Theoretical peak Stated by the vendor

Derived comparisons

3.5×

Formula
a ÷ b ratio v1
Inputs
  • lvdc Instruction execution time: 82 µs
  • agc-block-ii Instruction execution time: 23.4 µs
Rounding
half-up , 2 significant digits

Compares instruction-execution-time at cpu scope, obtained by add-instruction. Valid only within this comparability group, and reported to 2 significant digits — the precision of the least precise input.

Fitted to

Editorial notes

The Block II order code has 34 normal instructions against Block I's 11, and multiplication is 2.5 times faster than Block I at the same memory-cycle time. There is no floating-point hardware: the arithmetic unit is an adder with shifting gates.

Sources

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