The new CPUs introduced by Intel had to do not only with the LGA775 platform. Besides this promising platform, which is at the same time pretty useless from many points of view so far, Intel decided to “blow up” the budget processor market, too. Therefore, the company introduced a family of new budget processors also known as Celeron D. and although Celeron D is very similar to the predecessors, Celeron family, the new CPUs for low-cost systems promise to turn into a very prospective solution especially due to the new 90nm Prescott core they are based on.
It is no secret for you I assume that one of the key peculiarities of the Northwood based Celeron CPUs, besides their low price, is also a pretty low performance. Celeron is considerably slower than the youngest Pentium 4 processors, as well as the competing Athlon XP CPUs selling in the same price group (we have already discussed it in great detail in our article called Choosing a Budget CPU: 24 Value Processors from Intel and AMD in Our Lab). Overclocking didn’t help, as you remember. Therefore, the changes in the processor architecture were highly anticipated. Intel tried to resolve the performance issues by launching the new Celeron D family.
This article should help us to find out if they really managed to succeed or not.
Intel Celeron D: What’s New?
The differences between the inexpensive Socket478 Celeron processors and their elder brothers, Pentium 4 CPUs, were not very significant from the very beginning. These processors were made from the same semi-conductor dies as Pentium 4, but they had one fourth of the L2 cache memory and disabled Hyper-Threading technology. Moreover, Intel designed Celeron processors to support the slowest bus frequency of 400MHz. These differences were more than enough to turn a pretty fast Pentium 4 on Northwood core into a slower Celeron. However, Celeron processors still were pretty demanded firstly due to excellent branding, and secondly, due to their relatively low price.
What has changed once Intel announced their new Celeron D processor family? First of all I would like to point out that Celeron D is based on the new Prescott core, which we all know very well from the fast Pentium 4 processor models. You can read more about this processor core in our article called Intel Prescott: One More Willamette-like Slow Processor or a Worthy Piece? And in the meanwhile we will just list the major architectural differences between the current Prescott and the previous Northwood core.
- The use of new 90nm manufacturing process with “strained silicon” technology;
- Longer 31-stage execution pipeline;
- Enhanced branch prediction algorithm;
- Improved hardware and software data prefetch;
- Accelerated execution of certain commands: integer multiplication and shifts;
- Larger L1 data cache, 16KB big;
- Twice as much L2 cache memory;
- SSE3 SIMD instructions support.
I can’t say that all these changes are aimed at increasing the CPU performance in the first place. For instance, the longer execution pipeline does allow increasing the clock frequency even higher but in reality it reduced the CPU performance causing longer idling of the execution core when the bran prediction unit fails. So the overall situation with the Pentium 4 CPUs moving to the new Prescott core turned out pretty funny, I should say: all innovations are aimed at eliminating the negative effects of the longer pipeline. Moreover, as we have seen in our article called Massive Attack: Performance Tests of 14 Processors Priced at $200+ when Northwood and Prescott based CPUs work at the same clock frequency, the older core very often proves more efficient than the new one. However, you shouldn’t forget that Prescott based processors should be more scalable in terms of clock frequency, which is actually one of the main reasons for Intel to switch to this core.