After the introduction of the Pentium II, there were rumors of Intel working on a 266MHz Socket-7 Pentium MMX processor, code-named the Tillamook.  With current Pentium MMX 233's boasting a high yield, and overclockers pushing the limits of their chips by taking them up to speeds close to 300MHz a 266MHz Pentium MMX would be a severe threat to the Pentium II for those that didn't feel like jumping on the Slot-1 Bandwagon.  Intel realized this, however they also realized that not everyone could afford the high cost of a Pentium II, as well as the fact that the Pentium II produced too much heat to be used as a notebook processor. At the same time Intel was not ready to admit that their Slot Design had a flaw, and they were definitely not ready to go back to the Socket-7 world they had left behind...they needed a solution, and they needed it quickly.

Imagine all the power of a Pentium II, in the chip the size of a Pentium MMX.  That was Intel's vision, however they had to make this wonder-chip interface with the current Slot-1 Design of Pentium II motherboards that they had committed to so strongly just a year ago.  This chip would have to be geared towards the "low-cost" PC, for home/family use, which includes surfing the net, playing games, and running reference applications, etc...

Basically the demand for a low-cost Pentium II was made, so Intel, in response to this demand, removed two of the most expensive (and easily removable) parts from the Pentium II:  The L2 Cache, and the Cartridge casing.   By removing the L2 cache, you not only eliminate a considerable amount of heat, but you also decrease the price of the processor dramatically.  Removing the L2 cache also removes the need for active/passive cooling that covers the entire length of the cartridge, therefore removing the need for the casing, which drives the cost of the chip down even more. 

In the end, Intel produced the equivalent of a next generation Pentium MMX on a stick, a cache-less Pentium II, the Celeron.   Without the meaty qualities of the Pentium II how will Intel's latest Vegetarian creation satisfy the hunger of power users without a large budget?  Go to the fridge, grab some salad dressing, as AnandTech takes an in-depth look at low-cost PC's and Intel's Celery Stick.

A first look at the Celeron reveals that there is quite a bit missing from the card, but if you've ever seen the inside of a Pentium II Cartridge then the image of the Celeron will surely ring a bell.  Absent from both sides of the Celeron CPU Card are the L2 Cache chips that you'll find on its bigger brother, the Pentium II.  In the center of the card is a green CPU that closely resembles the likeness of a Pentium MMX, albeit about 10% smaller in size in comparison to the old 233MHz P-MMX.

With the heatsink off you can see the four holes surrounding the processor itself which are used to clamp the cooling unit to the card.   On the back of the card you'll notice the Intel logo a second time, as well as the printed part number and rated clock/bus speed.   At the present time the only type of Celeron available is the 266/66 unit, don't expect that to change anytime soon although there has been talk of a Celeron equipped with 256KB of L2 cache in the works. The card will fit into a standard Pentium II Single Edge Connector (SEC) Slot, meaning it will fit in any Pentium II motherboard, whether or not it will work is another story.  The Celeron itself was designed for use with Intel's new 440EX Chipset, essentially a tamed version of the highly successful LX AGPSet.

The 440EX Chipset, essentially a tamed version of the highly successful LX AGPSet, will be found on motherboards designed specifically for use with the Celeron weighing in at prices below $70.  With BIOS Support you can use the Celeron on older LX motherboards, and using a Celeron on a BX based motherboard isn't a problem at all.  The Celeron will not, however, work on older 440FX based motherboards.  In theory support for the Celeron could be provided by manufacturers of older 440FX products via a small flash of the BIOS, however the likelihood of that happening is very doubtful. 

While pre-release Celeron chips supported clock multipliers in excess of 4.0x, the retail chips are completely locked at 4.0x.   Meaning you cannot decrease nor increase the clock multiplier past 4.0x, regardless of what setting you choose with the Celeron it will default to the 4.0x setting...and by default, the chip will report itself as being a 66MHz Bus Pentium II processor.   Motherboards like the Supermicro P6SBA, that auto-detect what type of Pentium II you have, will not allow you even the option of making use of the 100MHz Bus Speed on the Celeron.

Like the Pentium II, there are two main methods of cooling the Celeron, you can either use the retail Heatsink, or a 3rd party Heatsink/Fan Cooling Solution.  The retail heatsink, manufactured by AAVID for Intel, is large enough to properly dissipate heat from the Celeron CPU while remaining small enough to eliminate the need for additional support for the unit.  The Celeron CPU Retention Set is much more low profile when compared to the Pentium II's Retention kit, but the installation is virtually identical.  You simply plug the left and right supports into the holes where the Pentium II Retention kit's threaded base would normally be and snap the Celeron into place. 

Cooling the Crunchy Green Exterior of the Celeron with a more active method of cooling, will allow for more room while overclocking, in spite of the already tight overclocking quarters conjured up by Intel.  How far can the Celeron go?  Let's find out...

As mentioned above, a Celeron 266 will run at virtually every speed its Cache-Equipped brother, the Pentium II - 266, will using a 4.0x multiplier.  Running at 300MHz (4.0 x 75MHz) and 333MHz (4.0 x 83MHz) isn't much of a problem, although you may want to buy a Fan for the CPU if you plan on overclocking it, as the retail Heatsink tends to get extremely hot after extended periods of use.

If you plan on overclocking your Celeron, you must take the initiative to check with the motherboard you plan on using with your processor to see if it supports the 75/83MHz bus speeds, otherwise you're pretty much out of luck.

Due to the lack of any L2 cache subsystem, the Celeron benefits greatly from increased bus speeds.  With Socket-7 systems, we have proven that an increase in bus speed increases performance considerably as a result of the faster access to the L2 cache.  In the case of Celeron, where there is no L2 cache to access at any speed, the System RAM picks up the slack, and the faster you can access the System RAM, the more your system benefits overall.  If it were possible, a Celeron running at 75 x 4.0 (300MHz), in comparison to a Celeron running at 66 x 4.5 (300MHz) would produce a performance difference much greater than if you compared a Pentium II 300/75 to a Pentium II 300/66 for that very reason.

If you remember back to AnandTech's test of the Pentium MMX, Cyrix 6x86MX, AMD K6, and Pentium II with and without L2 cache (Evolution of Microprocessors Article) the results proved that without L2 cache, the Pentium II became nothing more than a oversized Pentium MMX in Business Applications.  This is because most Business Applications use the Level 2 Cache as their loading/work space, meaning they can load their most frequently accessed data into the L2 cache and retrieve it later at a much faster speed than normal.  This makes things like opening a document in Microsoft Word, surfing the net, sending print requests to the printer, copying and pasting, and more common tasks much faster.  This is also why such tasks are the last to experience a significant performance boost by a simple upgrade of your processor.   Going from a Pentium MMX-233 to a Pentium II - 333, for example, won't yield a highly noticeable difference in how fast Microsoft Excel loads.  With the Business Application performance of a Celeron 266 around that of a Pentium MMX 200/233 who really needs more than that?  How many times have you found yourself complaining about how slow your Pentium MMX performs under Microsoft Office, Corel WordPerfect, or Lotus SmartSuite?  Unless you happen to have a keen eye for performance, the answer is most likely never.  But what makes the Celeron better than a Pentium MMX 233?

As mentioned throughout this article, the Celeron is nothing more than a cacheless Pentium II, meaning as long as the application you're running isn't too dependent on the functionality of a high speed Level 2 cache, there is very little difference between a Pentium II - 266 and a Celeron 266.  One obvious example of this would have to be idSoftware's Quake 2.  Quake 2 is notorious for being a FPU dependent game, in fact it is one of the most popular in the gaming scene today.  Well, since very few people have the budget to purchase Pentium II - 400 systems for the sake of playing Quake 2, and the Socket-7 processors out today just don't cut it as far as performance goes, the Celeron fits quite nicely into this market.   Imagine a < $200 chip capable of producing frame rates comparable to a Pentium II under Quake 2, what you're imagining is the Celeron.  Games like Quake 2 and Turok which are FPU intensive yet don't benefit much from the presence of L2 cache simply fly on the Celeron, especially when your pair this low cost solution with a Voodoo2 card.

As far as High End applications are concerned (such as CAD, Application Development, Image Editing applications, etc...), the Celeron is a few percent faster than a equivalently clocked K6, which isn't too shabby at all when you consider the other benefits the Celeron provides you with.  This is definitely not a High End microprocessor solution, under Windows NT the Celeron falls behind considerably performance-wise due to NT's extreme dependency on L2 cache.  If you plan on getting some work done under Windows NT you may want to stay away from the Celeron and stick to a K6/266 or a Pentium II - 233. 

So who would really want a Celeron?   Someone who is looking for average performance under Business Applications, the ability to run a few (if any) High End Applications at a decent speed, and someone who is really into getting the maximum performance out of his/her FPU Intensive games without having to sell their soul to idSoftware - that is the type of person that would really benefit from a Celeron.

If given the choice between a Celeron 266 and a Pentium II - 233, which should you chose?  If you fit the above description, and also plan on overclocking, pick the Celeron since it can run at 333MHz (it has a better chance of making it to 333 than a Pentium II - 233).  If you either, don't fit the above description, or don't plan on overclocking too much (if at all), then pick the Pentium II - 233.  At 233MHz the Pentium II will be faster than the Celeron 266, and the addition of L2 cache makes the processor a much better deal if you don't plan on overclocking it.

As far as future expandability goes, if you purchase a Celeron + BX Motherboard combo now, you can always upgrade to a Pentium II - 400/450 later on when the prices drop to a more realistic level, whereas with a Socket-7 system, you have no guarantee as to which upgrade path you will be able to choose with your current motherboard.  One thing you must take into consideration is that the Celeron won't dominate all FPU intensive games, a few games slated for release later this year or early next year make heavy use of both a processor's FPU and a system's L2 cache.   In those cases (depending on the dependency of the game on the L2 cache), expect sub-Pentium II performance, more or less about the speed of a Pentium MMX.  This is of course, just a speculation, since there is no way at all that we can predict how future software will perform on the Celeron.  Just be aware of the fact that there are some games coming out that will make use of the Celeron's strength, its FPU,  while at the same time exploiting its major weakness, its lack of any L2 cache.  If motherboard manufacturers begin adding their own Level 2 cache onto their 440EX based motherboards, then the Celeron will truly become the death to a considerable portion of the low-end market. 

As you can see, the Celeron isn't much of a Business Application Performer.  Weighing in at about the speed of a Pentium MMX 233 in Business Winstone 98, the Intel Celeron is a below average performer by today's standards, even in the Socket-7 market.  It does hold its ground though, considering that the lack of power in this department is made up for tremendously by its virtual domination of the gaming scene.