Key Features

  • 2MB L2 Cache
  • Execute Disable Bit
  • Enhanced Memory 64 Technology (EM64T)
  • Enhanced Intel SpeedStep Technology (EIST)

 

2MB L2 Cache

The Pentium 4 3.373EE and 600 Series Pentium 4 are both based on Intel’s new Prescott 2M Core, who’s most notable feature from an architectural standpoint is the huge 2MB of onboard L2 Cache, the most we’ve ever seen in a desktop CPU. Here we show comparison photos of the original Prescott Core and the new Prescott 2M.

Original Prescott Core

p1 Intel Pentium 4 660 & Pentium 4 3.73 Extreme Edition Review

Prescott 2M Core

p2 Intel Pentium 4 660 & Pentium 4 3.73 Extreme Edition Review

As you can tell from the pictures above, the most notable difference between the two cores is the size of the L2 Cache, with the 2M core effectively having double the L2 Cache of the original Prescott. The increase in L2 Cache should prove effective in CPU and Memory intensive applications where the CPU’s extra onboard cache will allow the CPU to forgo slower main memory when completing its assigned task. Die size and transistor count have also increased with the jump to the Prescott 2M core, from a die size of 112 square mm the Prescott 2M is now 135 square mm large, and from a transistor count of 125 million with the original Prescott, we now have a transistor count of 169 million.

Enhanced Intel SpeedStep Technology (EIST)

As transistor count increases, power consumption increases, and in turn heat increases as well. We all know how hot the original Prescott core got, so one would figure that the new Prescott 2M core would require a new heatsink fan design. However, that is actually not the case, the same reference heatsink fan is used on the new Prescott 2M, partly because Intel has included their SpeedStep power management technology to their new core. First found on Intel’s mobile Pentium M processors, SpeedStep scales frequency and voltage according to CPU load. Essentially SpeedStep underclocks your CPU when you’re surfing the internet and runs at rated frequencies under CPU-intensive applications, like video encoding.

There are three new mechanisms contributing to Enhanced power
management; Enhanced Halt State (C1E), Thermal Monitor 2 (TM2) and EIST. All
these mechanisms make use of lowering of multiplier and voltages to reduce
dynamic power consumption and lower leakage.

C1E is activated via Halt (idle) instruction execution and is
different to the current C1 halt state (90% of clocks are stopped, 10% run at
full speed) as it will also reduce frequency and voltage to the lowest
multiplier possible, in this case 14x on the Prescott 2M core. The reason why
Pentium 4 3.73Ghz Extreme Edition doesn’t feature EIST is due to the fact that
its multiplier is already running at its lowest which is 14.0 x 266Mhz.

TM2 Intel Pentium 4 660 & Pentium 4 3.73 Extreme Edition Review

TM2 operates via processor request based upon thermal load and
is a better implementation than the current TM1 since there is no drastic CPU
throttling effect in the case of high die temp. Like C1E, TM2 lowers multiplier
and voltage.

Finally, EIST operates via OS request based upon CPU load and is
commonly practiced on the mobile front to conserve precious battery power. A
lower frequency is used when the system is not utilized heavily and a higher
frequency is selected when under load.

Enhanced Memory 64 Technology (EM64T)

But why the need for 64-bit technology? It really comes down to memory addressing. In a 32-bit world, a 4GB memory address ceiling is enforced for every component in your system that initiates I/O commands. Moving to 64-bit allows us to expand the memory address ceiling all the way up 256TB, giving a tremendous amount of headroom for I/O components in the years to come.

Intel integrated 64-bit technology into the Pentium 4 through EM64T, 64-bit extensions compatible with AMD’s 64-bit technology that are extensions of the 32-bit x86 instruction set. This allows 64-bit Pentium 4 CPU’s to effectively run 32-bit software and finally gives the Pentium 4 the same 64-bit/32-bit flexibility the Athlon 64 has had in the market.

Execute Disable Bit

Another technology imbedded with the Prescott 2M is Execute Disabled Bit, which in conjunction with Windows XP Service Pack 2 helps to thwart security related threats such as buffer overflow attacks.

 

CPU Specs Comparison

Pentium 4 5XX

Pentium 4 6XX

Pentium 4 EE 3.46

Pentium 4 EE 3.73 GHz

Package

LGA775

LGA775

LGA775

LGA775

Processor rating

570, 560, 550, 540, 530, 520

660, 650, 640, 630

None

None

Clock frequencies

2.8 – 3.8 GHz

3.0 – 3.6 GHz

3.46 GHz

3.73 GHz

Bus frequency

800 MHz

800 MHz

1066 MHz

1066 MHz

Core

Prescott

Prescott 2M

Gellatin

Prescott 2M

Manufacturing technology

90nm, strained silicon

90nm, strained silicon

130nm, strained silicon

90nm, strained silicon

L2 cache

1024 KB

2048 KB

512 KB / L3 2048 KB

2048 KB

EM64T

None

Yes

None

Yes

Hyper-Threading technology

Yes

Yes

Yes

Yes

SIMD-instructions support

SSE, SSE2, SSE3

SSE, SSE2, SSE3

SSE, SSE2

SSE, SSE2, SSE3

Number of transistors

125 mln

169 mln

178 mln

169 mln

Die size

112 sq.mm

135 sq.mm

237 sq.mm

135 sq.mm

As we take a look at the side by side comparison of Intel’s most recent product families, we can see that Intel has chosen to keep 3.8GHz as the top end speed of the Pentium 4 and not scale up to 4GHz as was widely speculated earlier last year. In fact, it’s likely that Intel will not break the 4GHz barrier for quite some time as Smithfield, Intel’s Q2 dual-core part will likely tip the scale at 3.2GHz when it is released.

From the table, we can also see that Intel has decided to switch the Extreme Edition to the Prescott 2M core built on Intel’s 90nm manufacturing process. With the Extreme Edition being based on the same core as the 600 series, Intel is able to produce EE chips on a higher volume and at a lower cost than EE chips based on Gellatin. With their proven 90nm process, Intel can now take EE and standard 600 series cores from the same wafer, leading to more slightly lower prices on the EE front ($ 999 for the Pentium 4 3.73EE).

1pic Intel Pentium 4 660 & Pentium 4 3.73 Extreme Edition Review