by FastSite
02/20/2002 | 12:00 AM
Since the first Celeron CPU came into being, this processor family has been the overclockers' favourite, because most Celeron models boasted remarkable overclockability. It was possible to increase their clock frequency by 1.5 times, so that the performance of an overclocked Celeron CPU could easily catch up with an average High-End processor. Over the history of this CPU family there have been several overclocking leaders. At first, these were Celeron 300A CPUs based on Mendocino die, which rarely failed to reach the bar of 450MHz. Then there came Celeron 533A model on Coppermine-128 core that ran as far as 800MHz. In fact, their enormous overclockability was hit just by the younger Duron models that were able to climb up from 600MHz to 1GHz. But the time of all these CPUs is gone and the hearts of today's overclockers are free to welcome a new favourite.
If we analyze the genesis of CPUs with high overclockability, we'll see the following pattern. As a rule, in a group of processors built on the same core CPUs with the lowest clock frequency sport the best overclockability. The trend is pretty logical. Processors with the same core are potentially close in overclockability. Accordingly, slower models have broader horizons for overclocking. Therefore, it makes sense to pay special attention to oveclocking matters when CPUs based on a new processor core arrive.
Recently Intel has refreshed its Celeron CPU family and introduced the first models based on a new 0.13-micron Tualatin-256 die. The first processors built on this core were nominally clocked at 1.2GHz and didn't boast high overclockability - 1.5GHz was their highest point. Some time later Intel decided to replace the faster Celeron models (1GHz and 1.1GHz) based on the old 0.18-micron Copermine-128 core with Celeron CPUs based on Tualatin-256. That's how two new processors emerged - Celeron 1A GHz and Celeron 1.1A GHz. Due to their lower nominal clock frequency, they are supposed to have better overclockability than Celeron 1.2GHz. We positively couldn't help investigating their overclocking abilities. So, enjoy!
Although Celeron CPUs 1GHz and 1.1GHz based on Coppermine-128 and Tualatin-256 cores are priced at about the same level, please, keep in mind that their features are not the same. Even if we don't speak about their overclocking potential (it is evident that CPUs built on the 0.13-micron Tualatin-256 have better overclockability than those built on the 0.18-micron Coppermine-128), the performance of Tualatin-256 clocked at the same frequency as Coppermine-128 is higher. Processors built on Tualatin-256 core have a 256KB L2 cache, whereas the old Celeron CPUs with Coppermine-128 are equipped with only 128KB of L2 cache.
Sadly, Celeron processors with Tualatin-256 work on not all Socket 370 mainboards. The new Celeron CPUs belong to FC-PGA2 processors. The trouble is that the meaning of some socket pins has changed, so FC-PGA2 CPUs can work only on FC-PGA2-compatible mainboards based on i815 B-step, i810 B2-step, VIA Apollo Pro133T, Apollo Pro266T or ALi Aladdin Pro 5T.
If we compare the overclockability of Celeron CPUs based on Coppermine-128 and Tualatin-256, there is no doubt that the latter would be much better. First of all, it is for a finer 0.13-micron technology of Celeron (Tualatin-256), which results in a smaller core and subsequently lower heat dissipation - the main obstacle for every overclocker. The indirect evidence of this phenomenon is that 1GHz is about the top frequency for the 0.18-micron Coppermine-128 based Celeron CPUs. The maximum clock frequency you could overclock this core to was 1.1GHz. The faster models are made with a finer manufacturing technology. As for Tualatin-256, the highest clock frequency for them is at least 1.5GHz. Till recently, Celeron 1.5GHz CPUs built on this core was on Intel's roadmap. But as Intel wanted to move over the entire Celeron family to Pentium 4 architecture as soon as possible, Celeron 1.5GHz CPUs merely vanished from Intel's latest plans. As a result, the fastest Celeron CPU based on Tualatin-256 core will be clocked at only 1.4GHz.
For test purposes we took the slowest Celeron (Tualatin-256) CPU 1GHz. This processor is officially known as Celeron 1A GHz (the postfix "A" points out at the new 0.13-micron core). It works with 100MHz FSB and at 1.475V Vcore. We would like to stress that all Intel processors have a locked CPU multiplier, which is impossible to unlock. For instance, the locked multiplier of Celeron 1A GHz is 10x. This way, it can be overclocked only by increasing the FSB clock frequency.
CPU overclocking by means of FSB frequency increase has some advantages that are of special importance for Celeron CPUs. FSB frequency growth provokes not only an increase in the CPU clock frequency, but also tells on the memory, AGP and PCI buses. One of the things limiting the performance of Celeron based systems is a too slow CPU bus. It works at 100MHz and provides only 800MB/sec bandwidth. This is the lowest CPU bus bandwidth of all the contemporary CPUs. So, if we increase the FSB frequency in a Celeron based system, the performance will grow up not only due to the FSB frequency increase, but also to a faster CPU bus and memory subsystem. In Celeron based systems on Intel chipsets memory bus it clocked synchronously with the FSB. Intel 815 family supports asynchronously working memory and FSB. In this case, the memory frequency is decreased down to FSB-PCI, so normally this mode is not used at all.
In our testlab we overclocked Celeron 1AGHz (S-spec SL5VP). We would like to mention that Celeron (Tualatin-256) CPUs 1GHz and those shipped to OEMs have the same S-spec. Retail Celeron 1AGHz processors have S-spec SL5ZF and they have the same overclockability as their OEM brothers. Until Intel launches another stepping of Tualatin-256 core (the current version is A1-step), there'll be no other S-spec marking for Celeron 1AGHz. All Celeron CPUs based on Tualatin-256 core A1-step have CPUID 06B1. So, if you want to check the stepping of the CPU die, you need to look at the marking with S-spec or use some utility which shows the CPUID.
We overclocked our Celeron 1A on ABIT ST6 mainboard based on i815EP B-step. It offers a good bunch of overclocking features including FSB frequency adjustüóòå with an increment of 1MHz and a possibility to increase the Vcore. Before the tests we brought the Vcore of our Celeron CPU up to 1.6V.
Another thing that helped us to improve the overclocking results was an efficient cooling system. Intel made significant progress in FC-PGA2 CPU cooling: they provided the processors with a device called IHS (Integrated Heat Spreader). The device is a metal cover that hides the chip surface. It protects the chip from damages and spreads the heat over a vaster surface, which ensures better heat dissipation from the CPU to the cooler. For a better result we selected one of the latest coolers from Thermaltake, Volcano 7. This solution is equipped with a copper heart, a huge heatsink and a big fan. Its rotation speed varies depending on the surrounding temperature. Besides, in order to improve the heat dissipation again, we took silver containing thermal paste.
Now let us say a word about the results. In the above-described conditions we could easily overclock our CPU up to 1.53GHz (i.e. the FSB frequency would total 153MHz). However, as we checked the system's stability (one of the best tests for this kind of thing is still the game called Unreal), we found out that the system could not remain stable with over-150MHz FSB. Consequently, our Celeron 1AGHz eventually went as high as 1.5GHz.
New Celeron 1A CPUs based on 0.13-micron Tualatin-256 die proved up to our expectations: they are among the best-overclockable processors. Like their predecessors, slower Celeron models based on Mendocino and Coppermine-128 cores, Celeron 1A CPUs can be overclocked by 50%. Well, let's have a look at the performance gain we obtained as a result of overclocking.
During this test session we tried to define the performance of Celeron 1A CPU overclocked up to 1.5GHz. Needless to say that it makes sense to compare the performance of an extremely overclocked budget CPU not with rivalry families but with full-featured CPUs. Following this logic, we compared our Celeron 1A@ 1.5GHz sample with slower Intel Pentium 4 and AMD Athlon XP models.
Our Celeron based system included ABIT ST6 mainboard based on i815EP B-step chipset. This board works with PC133 SDRAM. We don't use DDR SDRAM mainboards to test Celeron CPUs any longer. Faster memory is useless here because of the limited CPU bus bandwidth. The Celeron processor overclocked to 1.5GHz worked with 150MHz FSB, so the SDRAM on this platform ran at the same 150MHz providing 1.2GB/sec bandwidth. Of course, for stability purposes, we used high-quality PC150 SDRAM from Mushkin. At 150MHz it works with CAS Latency 2.
Another platform built on Pentium 4 CPU included i845 chipset and PC2100 DDR SDRAM. We refused to install RDRAM, because it would make the system much more expensive. Besides, i845 is more promising and is more widely spread than the RDRAM i850 chipset.
The third system based on Athlon XP processor was assembled with PC2100 DDR SDRAM and VIA KT266, which is now the most popular chipset among the AMD CPU fans.
Finally, we configured our testbeds as follows:
| Intel Celeron | Intel Pentium 4 | AMD Athlon XP | |
|---|---|---|---|
| CPU | Intel Celeron 1AGHz Intel Celeron 1A@1.5GHz | Intel Pentium 4 1.5GHz Intel Pentium 4 1.6GHz Intel Pentium 4 1.7GHz Intel Pentium 4 1.8GHz | AMD Athlon XP 1500+ (1.33GHz) AMD Athlon XP 1600+ (1.4GHz) AMD Athlon XP 1700+ (1.47GHz) |
| Mainboard | ABIT ST6 (i815EP B-step) | MSI 845 Ultra-ARU (i845D) | MSI KT266 Pro2-RU (VIA KT266A) |
| Memory | Mushkin PC150 CL2 SDRAM, 256MB | PC2100 CL2 DDR SDRAM, 256MB | |
| Graphics Card | VisionTek Xtasy 6964 (NVIDIA GeForce3 Ti500) | ||
| HDD | IBM DTLA 307015 | ||
We ran all the tests in Windows XP.
First of all, let us have a look at the results we obtained in synthetic tests from SiSoft Sandra 2002. They'll help us to assess the individual performance of different CPU units and single out the weak points of each architecture we tested.
Tests of the CPUs' integer unit show that the overclocked Celeron processor is pretty good at integer arithmetic. That is, Pentium III architecture implemented in Celeron CPUs has no problems caused by an insufficiently powerful ALU. At the same time, don't forget that the low bandwidth of Celeron CPU bus will inevitably limit its performance as it processes the data which are out of L1 or L2 cache.
The FPU of our Celeron processor has also proven no worse than those of its rivals. Even Athlon XP with its powerful FPU clocked at the same frequency as Celeron CPU is just a few percents faster than its Intel counterpart. As it follows from the diagram, Athlon XP 1700+ (its actual clock frequency is 1.47GHz) is only 0.8% faster than Celeron 1.5GHz.
The SSE unit of Celeron CPU is an absolute No 1. If something is able to spoil the performance of this CPU, these can be only the restrictions of the memory bus bandwidth. We can only praise Intel for the perfectly developed Pentium III architecture. As we can see, at the same frequencies Pentium 4 turns out slower than Celeron CPU in all the synthetic processor tests. Unfortunately, for marketing reasons Intel sacrificed Pentium III architecture in favour of Pentium 4. We are really sorry they did it…
Here comes the main limiting factor of Celeron based systems. However hard Celeron CPUs are overclocked, the insufficient memory bus bandwidth remains a traditional stumbling stone. None of the modern CPUs, except Celeron, transfers only one data pack per clock along the CPU bus. Athlon XP is equipped with DDR bus, Pentium 4 - with QDR bus. Thus, there is no wonder that in this test the Celeron CPU is twice as slow as the other two racers.
As we summarize the results of synthetic benchmarks, we would like to highlight that overclocked Celeron CPUs have really good performance potential. Still, their too low CPU bus bandwidth prevent the processor from showing the best of its potential. So, we can say nothing definite about how this Celeron 1A CPU@ 1.5GHz will behave in real applications.
As usual, we would like to start with office applications.
The result of Celeron 1A@ 1.5 is quite high. It keeps up with Athlon XP 1600+ and is slightly ahead of Pentium 4 1.7GHz.
This part of SySmark 2001 measures the systems' performance in content creation applications. Celeron 1A@ 1.5 runs pretty fast again. We would like to draw your attention to the fact that as we overclocked Celeron 1A from 1GHz to 1.5GHz, this benchmark shows that its performance grew by 46%, which corresponds to the frequency growth. Such marvelous performance gain happened because we overclocked the Celeron CPU by increasing the FSB frequency. Thus, the other subsystems turned faster as the CPU frequency went up.
In business applications Celeron 1A@ 1.5 proves faster than Pentium 4, but lags behind Athlon XP.
We also ran several tests in a bunch of popular data compression applications. One of them measured how fast the systems could archive the data packs of big size (directories with installed Unreal Tournament) with the maximum compression, which loads the CPU quite heavily. For this purpose we used a widely-spread WinZIP archiving utility. So, the smaller value on the diagram denotes higher performance.
The too low CPU bus bandwidth and eventually too slow memory subsystem do not let Celeron with its excellent computational resources become a leader. All the Athlon XP CPUs are far ahead of Celeron 1A@ 1.5. Some consolation comes from the overclocked Celeron when it managed to outrun Pentium 4 1.5GHz and 1.6GHz, but it is more the failure of Pentium 4 rather than the triumph of Celeron 1A@ 1.5GHz.
We tested how fast the systems could encode mp3 files from WAV with the help of Lame codec. Here we measured the time needed to encode tracks grabbed from a CD into mp3 format at 128kps. Once again, the shortest time signals the best result.
In this test Celeron performed better than in the data compression test. Though the above described problems didn't let it catch up with the Athlon XP clan, all the Pentium 4 processors (including the one clocked at 1.8GHz) dropped behind Celeron 1A@ 1.5GHz.
As for encoding a video-stream into DivX Mpeg4, this task turned out to require higher memory and CPU bus bandwidths. As a result, our Celeron 1A@ 1.5GHz caught up neither with the slower Athlon XP, nor with Pentium 4 1.5GHz.
Science Mark test depicts the CPUs performance in typical math1ematical modeling applications. In this sphere Athlon XP family is the best. Apart from a powerful computational potential it has a high-performance memory subsystem. Pentium 4 CPUs, on the contrary, are no good calculators in spite of their fast memory and CPU buses: our Celeron 1A@ 1.5GHz contrived to outperform even Pentium 4 1.7GHz.
It is no secret that processors are most commonly overclocked for gaming needs. That is why we paid particular attention to testing Celeron 1A@ 1.5GHz in games.
Let us start with testing the CPUs in 3Dmark2001. The results are similar to those obtained in applications processing streaming data. Celeron 1A@ 1.5 works almost as fast as Pentium 4 1.8GHz, but it is not enough to keep up with Athlon XP family boasting the best-balanced architecture.
As we disabled hardware T&L unit, the CPU had to cope with extra calculations. That's where Celeron 1A@ 1.5 breaks ahead of Pentium 4 1.8GHz.
In Quake3 the results of Celeron 1A@ 1.5 leave much to be desired. It is slower than any Pentium 4 or Athlon XP CPU. Pentium 4 family is known for its high results in Quake3. As for Athlon XP CPUs, Celeron 1A@ 1.5 cannot catch up with them because of the limited data transfer rate with the RAM.
Higher resolutions don't bring about any changes in the line-up.
In Unreal Tournament Pentium 4 family usually doesn't have much to be proud of. That is why Celeron 1A@ 1.5 is far ahead of all the competing Pentium 4 CPUs. Moreover, Celeron with its 1.5GHz runs shortly after Athlon XP 1500+ that seemed unreachable in Quake3.
The rating in another game, Return to Castle Wolfenstein, looks very much like that in Quake3. This is no wonder at all - Return to Castle Wolfenstein is based on Quake3 engine.
At higher resolutions Celeron 1A@ 1.5 finally overtakes Pentium 4 1.5GHz.
Serious Sam: The Second Encounter is based on an engine of its own, so the results are ranked in a different way. Well, the trend is still familiar to us: Celeron 1A@ 1.5 overtook the entire Pentium 4 family but failed to reach the Athlon XP group.
At higher resolutions the situation remains unchanged. By the way, we would like to remind you that for our tests we selected a Pentium 4 based system with PC2100 DDR SDRAM. So, please, keep in mind that if this system had been built with an RDRAM mainboard on i850, it would have had better results.
Performance tests in strategies is a rare thing to see. The reason is very simple: modern CPUs are so fast that nearly any strategy runs with lightning speed. However, there appeared a strategy, which can tangibly load even an advanced modern CPU. We mean Civilization III. In order to check the performance we measured how long it took the systems to think about another move in a certain situation in the heaviest playing mode. As always, the shortest time is the best result. For Celeron 1A@ 1.5GHz this is a good chance to show what it is capable of: its performance is one of the best.
New Celeron 1A GHz based on Tualatin-256 core demonstrated remarkable overclockability, so that it can be listed among the best representatives of the Celeron family. It can be easily overclocked by 1.5 times, its clock frequency reaching that of the CPUs from faster families.
Speaking about the performance of Celeron 1A@ 1.5GHz, there are the following issues to consider. Pentium III architecture used in Celeron CPUs boasts good calculating potential and theoretically is comparable with the other modern architectures. But Intel "endowed" Celeron CPUs with a grave performance restriction - a CPU bus with low bandwidth. In most cases it doesn't let Celeron CPU reveal their potential. Even overclocking doesn't help: the processor bus of any other up-to-date CPU is at least twice as fast. So, Celeron CPUs overclocked up to 1.5GHz mostly cannot catch up with Athlon XP 1500+ processors. At the same time, they easily outrace slower Pentium 4 models working in systems with DDR SDRAM.
There is another issue to take into consideration. Celeron 1AGHz works in FC-PGA2 compatible mainboards only. Meanwhile, Socket 370 (FC-PGA2) will soon turn outdated. Celeron CPU 1.4GHz due in the Q'2 of 2002 will be the last processor for this socket. Afterwards the entire Celeron family will migrate to Pentium 4 architecture and Willamette-128 core.
Though it is clear that Celeron 1A@ 1.5GHz will be able to outpace faster budget CPUs for quite a while, it is no rival to Athlon XP family. Still, in most tests an overclocked Celeron CPU surpasses slower Pentium 4 models with ease. On the other hand, as long as Socket 370 has no further outlooks, Celeron 1A is unlikely to become as popular as its well-overclockable Celeron predecessors.
Nonetheless, the example of Celeron 1A CPUs may serve as an illustration to how unexpected but pleasant overclocking results can be. We believe, it would be unwise to neglect this possibility :)