X-bit labs

LGA775: New CPUs and Chipsets (page 14)

Category: CPU

by Ilya Gavrichenkov

[ 06/21/2004 | 06:57 PM ]

New CPUs

Together with the new Intel 925X Express and Intel 915 Express chipsets, the company also announced a few new processors from the Pentium 4 and Pentium 4 Extreme Edition families. Although the new CPUs do not differ that greatly from the predecessors from the architectural point of view, they still boast a few innovations, which have mostly to do with the marketing, I believe. The new CPUs are designed in LGA775 form-factor, which should replace the current Socket478, and are marked in a different way. Now the CPUs are no longer marked with their actual working frequency, but feature the so-called “processor number”. We are going to tell you more about these new things later today, and now take a look at the main characters of our today’s story:

Prescott CPUs. Socket 478 on the left, LCG775 on the right.

The shift to a new i925/i915 platform is very closely connected with the new LGA775 socket. According to Intel’s plans, all new mainboards based on the freshly announced chipsets should come equipped with the new processor socket. Although no one can actually prevent the mainboard makers from breaking this undeclared rule, most mainboards based on the new Intel chipsets will come with LGA775 socket. That is why together with the new chipsets announcement, Intel has also released the whole bunch of CPUs designed in LGA775 form-factor. Today this processor family includes a few Pentium 4 5XX models , which are actually none other but the regular Pentium 4 processors on the 90nm Prescott core, and a Pentium 4 Extreme Edition 3.4GHz CPU. Note that the new LGA775 family from Intel includes no budget Celeron CPUs and no CPUs on Northwood core. However, LGA775 Celeron processors are about to come out pretty soon. As for Pentium 4 on Northwood core, we are very unlikely to ever see them in LGA775 form-factor at all.

So, let’s see what Intel CPUs are already available for the LGA775 platform:

You are already familiar with Prescott based processor from the previous article, which you can find in the CPU section. The new solutions announced today differ only by the form-factor:

However, I should point out that the new Pentium 4 (Prescott) CPUs should be based on the new D0 core stepping, while the Pentium 4 processors we tested a while ago were based on the C0 core stepping. The shift to the new core stepping has nothing to do with the change of the processor form-factor. The migration to the new Prescott core stepping is a pre-planned thing intended to reduce the heat dissipation and increase the frequency potential of the 90nm core. It actually allowed Intel to introduce a 3.6GHz CPU today called Pentium 4 560.

As for the Pentium 4 Extreme Edition 3.4 for LGA775, it is a total analog of the Socket478 processor, we tested not so long ago.

However, note that the use of new processor packaging for this solution did result into a slight heat dissipation increase. All in all, electrical and thermal characteristics of the LGA775 family look as follows (for a more illustrative comparison I also included the data for the Socket478 models):

This way, despite all Intel’s attempts and the use of new D0 core stepping in Pentium 4 (Prescott), the heat dissipation of the LGA775 models of these CPUs got higher. However, this is not going to lead to any drama this time. Mainboards with LGA775 socket are designed taking into account all specific power consumption and heat dissipation requirements set by the new processors. Moreover, Intel has also designed a new more efficient cooling system for its new CPUs: LGS775 coolers feature new retention mechanism and are of much bigger size.