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Review: Intel Pentium 4 3.4GHz Prescott

by Tarinder Sandhu on 9 May 2004, 00:00

Tags: Intel (NASDAQ:INTC)

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Appearance and specs.

There's more to cloud the issue. It makes implicit sense to assume that a die shrink (0.09-micron) and accompanying voltage reduction (~1.4v) would lead to a cooler-running processor. What that doesn't take into account is that heat is now concentrated in a smaller area. 125 million transistors, amongst other processor hardware, occupy a space of no more than 112mm². Our research has shown that a 3.4GHz Prescott runs at up to 12c warmer than an equivalent Northwood. Intel's own figures quote a <100w TDP (Thermal Design Power). It's a warm processor, no doubt about that.

There's nothing to distinguish our sample 3.4GHz semi-unlocked Pentium 4 Prescott from any other. For the record, the CPU had multipliers available from 14x through to 17x (default). As with all later Northwoods, it runs off a native 200MHz FSB.

Socket 478, but for how much longer?. We're adamant the 3.4GHz model will be the last. Socket 775 is all set to go, with improvements to the core logic affording a touch extra performance. For now, though, Prescotts will function on most S478 motherboards. It's up to motherboard manufacturers to release compatibility BIOSes.

Larger L1 and L2 data caches are an obvious difference, so is the reported 0.09-micron manufacturing technology. CPU-Z can only tell you so much. On reflection, there's enough difference between Northwood and Prescott cores to warrant a separate review in itself.

Associativity, or degree of relatedness is up. So is latency, apparently.

Let's sum it up in a table.

Name Pentium 4 3.4GHz Prescott Pentium 4 3.4GHz Northwood Pentium 4 3.4Ghz Extreme Edition Pentium 4 3.2GHz Prescott AMD Athlon 64 Model 3400+ AMD Athlon 64 FX-53
Clock speed 3400MHz 3400MHz 3400MHz 3200MHz 2200MHz 2400MHz
L1 cache 28kb* 20kb 20kb 28kb* 128kb 128kb
L2 cache 1024kb 512kb 512kb 1024kb 1024kb 1024kb
L3 cache - - 2048kb - - -
FSB 200MHz quad pumped 200MHz quad pumped 200MHz quad pumped 200MHz quad pumped 2200MHz (core speed) 2200MHz (core speed)
Pipeline length 31 stage 20 stages 20 stage 31 stage 12 stage 12 stage
Socket S478 (for now) S478 S478 S478 (for now) S754 S940
Manufacturing process 0.09-micron 0.13-micron 0.13-micron 0.09-micron 0.13-micron 0.13-micron
Transistor count 125 million 55 million 169 million 125 million 106 million 106 million
CPU die size 112mm² 127mm² 237mm² 112mm² 193mm² 193mm²
Voltage ~ 1.375v ~1.525v ~ 1.525v ~1.375v 1.5v 1.5v
Memory support (now) DDR400 DC DDR400 DC DDR400 DC DDR400 DC DDR400 SC DDR400 DC Registered
Other SSE3, HT, Higher L1 data cache associatively Last Northwood 2MB L3 cache Expensive SSE3, HT On-die controller 32/64-bit

* - The Pentium 4 Northwood has 8kb of L1 data cache (4-way associativity) and 12kuops L1 trace execution cache. The Prescott has 16kb of L1 data (8-way associativity) and the same 12kuops. The question that's been on our lips is whether the Prescott's technological advantages can make up for the performance shortfall that a much longer pipeline will inevitably create. We're about to find out.