Intel Prescott: the benchmarks

Intel Prescott: the benchmarks

Summary: Intel's new 'Prescott' Pentium 4 has double the L1 and L2 cache of its 'Northwood' predecessor. An extended 31-stage pipeline accounts for the fact that the new chip is mostly slower than the CPU it replaces

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TOPICS: Hardware, Reviews
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Caches, pipelines and power dissipation
The new Prescott CPU has more cache memory than its Northwood predecessor: both the L1 and the L2 caches are now twice as large as before, at 16KB and 1MB respectively. The Prescott chip also supports SSE3, which includes 13 extra PNI (Prescott New Instructions) commands. However, no applications yet support the new Prescott instructions, so they are currently irrelevant in practice. Larger L1 and L2 caches should boost Prescott’s speed. The fact that this is mostly not the case -- Prescott is sometimes slower than previous Pentium 4 variants -- is because the chip’s command pipeline has been extended. Think of the pipeline as an assembly-line with several stages: the more stages assembly line has, the faster can it run, in theory. But if the parts (instructions and data) on the assembly-line are not in the correct order, the line must be stopped, corrected, and restarted. Intel tries to balance this disadvantage with larger caches, which offer faster access to instructions and data than conventional main memory. But larger caches also mean that the power dissipation of the chip rises. The following tables give the results from a variety of PC systems.

Power dissipation (Watts, with Radeon 7000 GPU)

Motherboard
CPU
Idle
(no load)

Maximum
(full load)

Cool 'n' Quiet

Asus P4C800 P4 3.2E GHz
(Prescott)
114
192
n/a
Asus P4C800 P4 3.2 GHz (Northwood)
76.5
144
n/a
Intel D875PBZ P4 3.2E GHz
(Prescott)
96.9
188
n/a
Intel D875PBZ P4 3.2 GHz (Northwood)
62.7
127
n/a
Asus K8V Deluxe Athlon 64 3400+
113
119
71.7
Asus K8V Deluxe Athlon 64 3200+
106
115
70.6
Fujitsu Siemens D1607 Athlon 64 3400+
107
114
65
Fujitsu Siemens D1607 Athlon 64 3200+
101
105
62


A PC with standard components and the new Intel Prescott chip dissipates nearly 50 Watts more under full load than the same system with the previous-generation Northwood chip. In Idle(no load) mode, the Prescott system still uses nearly 35 Watts more.

Power dissipation (Watts, with Radeon 9800 Pro GPU)

Motherboard
CPU
Idle
(no load)

Maximum
(full load)

Cool 'n' Quiet

Asus P4C800 P4 3.2E GHz (Prescott)
165
248
n/a
Asus P4C800 P4 3.2 GHz (Northwood)
125
179
n/a
Intel D875PBZ P4 3.2E GHz (Prescott)
145
242
n/a
Intel D875PBZ P4 3.2 GHz (Northwood)
113
182
n/a
Asus K8V Deluxe Athlon 64 3400+
167
174
120
Asus K8V Deluxe Athlon 64 3200+
158
168
120
Fujitsu Siemens D1607 Athlon 64 3400+
157
166
114
Fujitsu Siemens D1607 Athlon 64 3200+
148
156
110

A high-end system with a 256MB Radeon 9800 Pro GPU and Prescott CPU dissipates nearly 250 Watts under full load. At nearly 200 Watts, the same system with the Northwood Pentium 4 uses considerably less power. AMD’s Athlon 64 3200+ under full load dissipates nearly 80 Watts less than the Prescott system. But the Athlon 64 has a disadvantage: motherboard manufacturers do not yet support all of the AMD chip’s power saving modes, which explains the comparatively small differences between no-load operation and full load. Only if AMD's Cool ' n ' Quiet mode is activated does the Athlon 64's power dissipation drop significantly.

Topics: Hardware, Reviews

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6 comments
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  • When will IT departments realise that Intel processors are overpriced, over-hyped and over heated? Choosing AMD processors will be cheaper up front and cheaper in the long run (less power being used).

    Unless the company wants to have a distributed, always on, heating system, there is now no reason to choose Intel over AMD.
    anonymous
  • Thanks for the great review. It was good to see a test that test each application/game in different configurations to find trends... Great job!
    anonymous
  • Thanks for the only slightly Intel-biased review (Dual DIMMs give the Intel mobos dual-channel RAM over AMD's single-channel single DIMM). While this doesn't make the Intel CPUs dominate the tests, it does make them look not quite as bad as they really are.

    I'll remember to look for more reviews on ZDNet in the future - to make sure that I avoid them.
    anonymous
  • re. the previous comment:
    Athlon 64 features only a single channel memory interface. Therefore it is irrelevant to have two DIMMs installed. The Athlon FX offers a Dual-Channel-Interface. With this processor it is important to have two DIMMs installed to get the best performance out of it, as with P4 systems.
    anonymous
  • re: Dual-Channel

    Sorry Kai, I was thinking about the socket 940 FX.

    Also, I shall retract my statement about ZDNet. After further review, some of the benchmarks you performed are different enough from the "standard" that (when balanced with other reviews) helps to paint a better overall performance picture. Thanks.
    anonymous
  • Well, gotta say, there might be some hope for ZDNet afterall. None of the usual Intel butt-kissing and making excuses for whenever it does worse than its competition.

    And I'm impressed by the fact that you're using F1 simulations to do some testing of the hardware. Haven't seen that anywhere else. You must be an F1 fan.
    anonymous