Intel Celeron : Avoid like the Plague or a Hidden Gem ? (Intel Celeron Processors in general)

Member Name: isvikthere

Product:	Intel Celeron Processors in general
Date:	17/09/03 (2305 review reads)
Rating:

Advantages: affordable, certain models like overclocking, intel product so well supported

Disadvantages: at intended speeds poorer performance

Introduction

Lately I've been browsing through the Dooyoo contributions on the Intel Celeron processor and I've stumbled on some misconceptions that seem to surround this budget processor made by Intel. In one case I read someone claiming the Celeron 1800 he bought was not able to perform as good as his trusty old AMD K6-2 533Mhz. This is nonsense of course. I'm sure there was another cause for this.

But this is exactly what a Celeron is, it is a line of processors launched by Intel to offer a cheaper alternative to their high-end desktop line of processors. Most of these misconceptions can be attributed to the fact that people don't really understand what really distinguishes the Celerons from the Pentiums-2/3/4. Throughout their life Celerons followed the evolution of the Pentium II, III and 4 line of processors, be it from a distance, so always one or two steps behind, both in top processor speed as in integrated technologies (MMX/SSE/SSE2, etc.)

History

I apologise in advance but to really make things clear one has to delve into the heart of the beast and there is no way one can do this without techtalk.

First and for all let it be clear that there are two important factors - there are of course others [see AMD's succesful range of XP and MP processors that, although operating at inferior frequencies/speeds, can surpass the Intel processors] - that determine a processor's performance:

1. The overall processor speed :
This overall speed is determined by the busspeed and a multiplier factor. From the Pentium 2 processors onwards Intel locked this multiplier firmly down and to this day no one has yet found a way around this. (This contrary to the AMD Athlon processors where ways were found to unlock them). The reason for this is simple : as Intel was aware and watched with an evil eye lots of people experimenting with the very first line of Pentium processors trying to achieve t
he highest processor speeds by combining maximum busspeed with the highest multiplier factor their motherboard would allow.
The user's philosophy behind this was : Why should one pay for a more expensive processor if through experimenting with the various multipliers and busspeeds present on the motherboards of the era you can achieve the same overall processor speed for less money ?

2. The amount of level 1 and level 2 cache the processor is using.
Cache memory is like any other type of memory with the difference that the Level 1 and Level 2 cached is adressed directly by the processor. From the very first Pentium onwards Level 1 cache has always been on the processor itself. Not so for Level 2 cache (see further).

Celeron processors first came to be after the launch of the Pentium II processors. Intel realised quickly that their new line of processors was carrying a pricetag too hefty for some people, so to compete with the then popular line of the cheaper AMD K6 and K6-2 line of processors (and also IBM and Cyrix) they created the cheaper Celeron.


Cache me if you can

Alhough any Celeron processor itself is physically almost identical to the Pentium-line of its generation there are some major differences. The biggest difference is in the L2 cache.

The Pentium II processors needed the big brown Slot 1 to be installed because at that time the Level 2 (size= 512kb) cache was not on the processor but right next to it on the green PCB card in the form of two memory chips of 256kb. The very first line of Celerons (266 and 300) had no Level 2 cache whatsoever which gave them rather poor performance compared to the Pentium2s and other brand Pentium1-type processors - which had their Level 2 cache on the motherboard (sometimes as much as 1Mb) . These first Celerons were however quite easy to overclock especially as they were not hindered by the possible limitations some memory chips installed with the Penti
um2-processors imposed on busspeed. Still their overall performance was nothing to boast about as the total lack of level2 cache was giving them too much of a performance handicap even at overclocked speeds.

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Overclocking

Overclocking a processor is dead simple : For intel processors from the Pentium2s onwards you run the processor at a higher busspeed than it was intended to run at, sometimes, because of the higher frequency attained, you need to provide the processor with more juice (a higher voltage) in order to allow it to operate at this frequency without hiccups. On modern motherboards both these settings can be accessed from within the BIOS (the Basic In and Out System) at startup.
For AMD processors if you manage to unlock the multiplier you can also experiment with this factor.
-----------------

From the PentiumII-300 onwards this line of processors were now running at 100Mhz busspeed. The Celeron processors however remained at the same busspeed of the first range of Pentium2s (233/266) which was 66Mhz. The then launched new A-series of Celerons (starting with the 300A) did receive one fourth of the level 2 cache (128Kb) that the Pentium2s had. But this time, and in this respect the Celerons were more advanced than those Pentium2s, because the level 2 cache was now ON the processor die itself (and not next to it on the PCB) and thus running at the same overall speed as the processor.


Celeron 300A @ 450Mhz

All this made e.g. the Celeron 300A processor a dreamchip for overclockers, which simply by running it at 100Mhz busspeed instead of the intended 66Mhz combined with the fixed 4.5 multiplier gave you an almost instant 450Mhz processor with its Level 2 cache running at the same speed. It was quite easy to do this as the motherboards of the era (even those made by Intel themselves !) had to provide both the 100Mhz busspeed for the Pentium 2s AND the 66Mhz busspeed for the Cel
erons and first generation Pentium2s.

66Mhz x 4.5 was 300 but 100Mhz x 4.5 made it 450

So you simply ran your Celeron at the busspeed intended for the latest Pentium2s.

Of course motherboard manufacturers other than Intel pushed things even further by offering you speeds outside the basic 66 and 100 Mhz settings (104/112/133). And when the jumperless motherboards came to be you no longer had to worry getting confused by the jumpersettings required. (Jumpers are small connectors you can place or move around yourself, closing or opening bridges/switches to achieve certain speed or voltage settings on your motherboard).

Thus through overclocking the Celeron 300A's performance was as good as the much more expensive PentiumII 450 processor which had its four times bigger cache running at only HALF the processor speed. The later 333, 366 , 400, 433 and 466 celerons gave you less chance of a successful overclock because of their higher multiplier. However Intel corrrected this advantage for the Celeron because from the Pentium3 onwards Level2 cache is always integrated on the processor itself thus garanteeing that a pentium 3 or 4 would always perform better than a Celeron even when run at identical frequencies especially since the Pentium 3 or 4 processors either had in their core double and later on again four times the amount of Level2 cache of the Celerons.

But from the launch of the first Celeron A-series on their success has always been dependent on their ability to overclock with some models being better suited than others. It allowed people that didn't want to spend their cash on the expensive Pentium2-3-4 processors to acquire a much cheaper processor that through overclocking could approach the same performance. The conditions for successful overclocking were based first on the Celeron core (the heart of the chip) being identical to one of the top-line processors but with a low fixed multiplier. So
once a new generation of Celerons is launched based on the latest technology of their expensive relatives you have the most chance of a successful overclock as with the first of a new generation the multiplier will be at its lowest (for lowest processor speed) this is then steadily being raised by Intel until maximum overall speed for this technology is reached and they then have to resort to new technologies for a new generation of processors to arrive.

As Celerons consistently are intended to run at lower busspeeds than the topline Pentiums (2/3/4), simply by raising the busspeed to the same level as the topline Intel processors you give performance an enormous boost and as their manufacturing technology is the same you can expect a high successrate with your overclock. Don't forget that the higher the (fixed) multiplier the lesser your chances on success. However, as said, even at the same overall speed they will never perform as good as their big brother because of the consisent lower amount of Level2 cache they are equipped with. Also Intel often Intel skips a generation before passing on a new technology (e.g. MMX or SSE/SSE2) from the Pentiums down to the Celerons.

Still even at its intended speed (so without any overclocking at all) the Celeron is not that bad a processor giving you more or less value for money although with the consistent pricegap between AMD and Intel Processors if you don't intend to overclock you are better off both financially and for overall performance with an AMD processor. But because it is an Intel processor just like its Pentium (2/3/4) brother it will be less fussy for cooling or for power consumption. In my experience all Intel procesors (Celeron or not) are built with higher tolerances (more headroom) than their AMD counterparts, which seem to be sold with less margin and are thus more fussy in the fields of cooling and powerfeed.


Overclockers all-times Hitparade of Celeron processors <
br>
1. Celeron 300A

intended to run at 66x4,5 but almost all of them ran at 450 (100x4,5)Mhz and some even went up to 504Mhz (112x4,5) it was the first of the Celerons with onboard L2-cache

2. Celeron 533A/566A

max.speed of 840 (112x7.5) or 850 (100x8.5)Mhz or even more achieved almost effortless

3. Celeron 1800/2000

between 2600 Mhz to 3Ghz possible

 remember : (maximum) overclock often requires a higher processor voltage (vcore) setting



CONCLUSION

Over time some specific models of the Celeron series were/are an overclockers' dream. However even run at their standard speed it is still a decent Desktop processor with sufficient performance for people not hooked on playing the latest of games or not involved in video editing or other high profile multimedia applications. At identical speeds their performance is however inferior to their Pentium or AMD counterparts. For the Pentiums this is logical at this is exactly why Intel created the Celeron. In the battle between AMD processors and Celerons the latter benefit from the fact that they are less fussy with cooling and powerfeed so you save money by needing no other ventilator than the standard solution provided with boxed Celerons.

Cheers,
ViK

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