Hi,
At 11:45 PM 6/22/2001 +0100, Michael Bell wrote:
>But they clearly don't care about it on the P4:
>
>Command Ticks on P2/P3 Ticks on P4
>MOV 1 1
>ADD/SUB 1 1
>ADC/SBB 2 8
>MUL 4 14-18
>SHR/SHL 1 4
Evaluating an architecture based on just latencies can be very misleading.
For example the P4 has longish latencies on the SSE2 instructions that
prime95 uses (6 for a load, 6 for a mul, 4 for an add). However, there is
enough parallelism available that these latencies are almost completely
hidden.
Other architecture features that may well be more important:
Cache structure & memory bandwidth
Number of registers (to help programmer expose parallelism)
Branch prediction and miss penalties.
And many, many more.
That said, the Athlon is a better performer for most applications today.
The P4 was designed for higher clock speeds and memory bandwidth.
Time will tell if Intel can ramp up the CPU speed to offset the Athlon's
advantages.
Regards,
George
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