by Ilya Gavrichenkov
06/25/2004 | 06:15 AM
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.
<%BANNER[article]%>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.
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.
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.
As for our today’s heroes, Celeron D CPUs, their clock frequencies haven’t yet exceeded those of the previous generation Celeron processors, so that the top models of both families now work at 2.8GHz. However, the transition of the budget Celeron processors to the new Prescott core may appear much more beneficial than in case of Pentium 4 CPUs. It can be explained by the fact that besides the changes resulting from Prescott’s architectural differences from the previous core, the new Celeron acquired one more very important feature, which has nothing to do with the processor die structure. Unlike the previous generation Celeron processors using 400MHz Quad Pumped Bus, Celeron D will support 533MHz bus. Keeping in mind the fact that the system bus bandwidth has a great influence on the performance of CPUs with NetBurst architecture, we have every right to expect the new Celeron D processors to prove noticeably faster than the predecessors.
Let me sum up all the technical details in a table for you:
| Intel Celeron D | Intel Celeron | Intel Pentium 4 | Intel Pentium 4 |
Processor core | Prescott | Northwood | Prescott | Northwood |
Socket | Socket 478 | Socket 478 | Socket 478, LGA775 | Socket 478 |
Maximum clock frequency | 2.8GHz | 2.8GHz | 3.6GHz | 3.4GHz |
Manufacturing technology | 0.09micron, | 0.13micron | 0.09micron, | 0.13micron |
Number of transistors | 125 mln. | 55 mln. | 125 mln. | 55 mln. |
Die size | 112 sq.mm | 131 sq.mm | 112 sq.mm | 131 sq.mm |
L1 cache for data | 16KB | 8KB | 16KB | 8KB |
L1 cache for instructions | 12000 uops | 12000 uops | 12000 uops | 12000 uops |
L2 cache | 256KB | 128KB | 1024KB | 512KB |
Bus frequency | 533MHz | 400MHz | 800MHz | 533, 800MHz |
SIMD instructions | SSE3/ SSE2/ SSE | SSE2/ SSE | SSE3/ SSE2/ SSE | SSE2/ SSE |
Hyper-Threading technology | None | None | Yes | Yes |
This way, Celeron D boasts twice as large L1 data cache and L2 cache (16KB and 256KB respectively), support of additional SSE3 SIMD instructions, faster 533MHz bus and all other architectural improvements resulting from a shift to 90nm Prescott core. Among the drawbacks, I should first of all mention the longer pipeline causing notable performance slowdowns while the clock frequency remains unchanged. Later today we will see how this is going to affect the performance in real applications, and in the meanwhile let’s take a closer look at the actual CPU.
The new Celeron D processors are selling in Intel’s common boxes, which are actually a little bit different from those the older Celeron processors were coming in.
I would like to point out right away that all Celeron D processors are marked in a new way: not with the clock frequency, but with the so-called “processor number”, which we have already told you about in our recent review called: LGS775: New CPUs and Chipsets. However, the stickers carry not only the number, but also a couple of formal specifications, such as L2 cache size and bus frequency:
However, I would like to offer you a table with all the markings and corresponding specifications of Intel’s desktop processors, just in case:
Brand | Processor number | Core | Clock frequency | Bus frequency | Cache memory | Intel Technologies |
Pentium 4 | 720 | Prescott | 3.73GHz | 1066MHz | 2MB L2 | HT |
580 | Prescott | 4.0GHz | 800MHz | 1MB L2 | HT | |
570 | Prescott | 3.8GHz | 800MHz | 1MB L2 | HT | |
560 | Prescott | 3.6GHz | 800MHz | 1MB L2 | HT | |
550 | Prescott | 3.4GHz | 800MHz | 1MB L2 | HT | |
540 | Prescott | 3.2GHz | 800MHz | 1MB L2 | HT | |
530 | Prescott | 3.0GHz | 800MHz | 1MB L2 | HT | |
520 | Prescott | 2.8GHz | 800MHz | 1MB L2 | HT | |
Celeron D | 350 | Prescott-256 | 3.2GHz | 533MHz | 256KB L2 |
|
345 | Prescott-256 | 3.06GHz | 533MHz | 256KB L2 |
| |
340 | Prescott-256 | 2.93GHz | 533MHz | 256KB L2 |
| |
335 | Prescott-256 | 2.8GHz | 533MHz | 256KB L2 |
| |
330 | Prescott-256 | 2.66GHz | 533MHz | 256KB L2 |
| |
325 | Prescott-256 | 2.53GHz | 533MHz | 256KB L2 |
|
Celeron processors, unlike Celeron D, will retain the frequency marking. This fact is going to become one more external difference of the new budget CPUs from Intel.
The exterior of the new Celeron D is very similar to that of the old one. Look:
Intel Celeron D on the left, Intel Celeron on the right
As we see, there is no mention about the new rating on the CPU itself, only the technical specifications are listed. The reverse side of the new Celeron D carries all electronic components typical of the Prescott based processors. The info we get from the diagnostic utilities about this CPU looks as follows:
As you can notice, Celeron D is still based on the old Prescott core with C0 core stepping. The new D0 stepping is now used only in the newest Pentium 4 processors designed for the LGA775 form-factor. As you remember, C0 core features slightly worse frequency potential and higher heat dissipation. However, Celeron D with smaller L2 cache and 2.8GHz core clock frequency this is not that critical. Therefore, Celeron D will hardly ever move to the new core stepping at all.
We have already paid due attention to the cache structure and memory subsystem organization in our extensive theoretical article devoted to the new processor core (see our article called Intel Prescott: One More Willamette-like Slow Processor or a Worthy Piece?). However, it is evident that disabled three fourths of the L2 cache should somehow tell on the characteristics of the cache memory subsystem by the new Celeron D processors. Let’s compare the L2 cache of the new Celeron D with that of Pentium 4 CPU based on Prescott core:
Intel Celeron D
Intel Pentium 4 (Prescott)
In other words, the smaller L2 cache of the Celeron D processor brought the number of associativity zones to four. As you remember, Celeron based on Northwood core features only two associativity zones. This way, the cache memory of the new Celeron D theoretically is not only larger, but also better organized than that of Celeron (Northwood).
However, despite slightly different size of the associativity zones of the fully-fledged Prescott and its version cut-down to fit into the Celeron D concept, the L2 caches of Pentium 4 (Prescott) and Celeron D are equally fast. To prove this point let me offer you the results of our measurements of the memory bandwidth and its latency when working with data blocks of different sizes. The measurements were carried out with Cache Burst 32 utility:
The obtained results indicate that the cache-memory in Celeron D processors works as fast as the cache memory of Pentium 4 processors based on Prescott core. At the same time I would like to draw your attention to the considerably higher performance of the Celeron D during work with the system memory, compared with what we saw by the previous generation Celerons. I have already pointed out the reasons for this positive change above: firstly, higher bus frequency and secondly, enhanced data prefetch mechanism implemented in the Prescott core.
One of the consequences of the Pentium 4 transfer to 90nm Prescott core appeared a considerable growth of the heat dissipation and power consumption. So what does the situation look like with the new Celeron D processors?
Processor clock frequency | Celeron D (Prescott), TDP | Celeron (Northwood), TDP |
2.8GHz | 73W | 68.4W |
2.7GHz | - | 66.8W |
2.66GHz | 73W | - |
2.6GHz | - | 62.6W |
2.53GHz | 73W | - |
Nothing surprising actually: the transition of budget CPUs from Northwood to Prescott core just like in case of Pentium 4 resulted into higher heat generation. However, I would like to stress that this growth is still lower than in case of Pentium 4. For example, Celeron 2.8GHz started to generate 6.7% more heat while the heat generation parameter of the Pentium 4 on 130nm and 90nm cores differs by more than 27.6%.
However, despite this relatively big increase of the heat generation, the boxed Celeron D processors are equipped with a new type of cooler with a copper heart and radially directed ribs guiding the ousted air flow around the cooler and the processor more efficiently.
I also have to say that this cooler looks very much like the coolers for LGA775 platform. It is just a little bit smaller and the fan is provided with somewhat smaller blades.
Speaking about heat dissipation I couldn’t help carrying out a practical experiment. We measured the real temperatures of the four CPUs: Pentium 4 CPU onPrescott core, Pentium 4 CPU on Northwood core, Celeron CPU on Northwood core and Celeron D CPU on Prescott core all working at 2.8GHz. For our tests we used one and the same cooler from the boxed Pentium 4 (Prescott) 2.8E GHz shipment. The values were delivered by the on-die sensor. We measured the minimal CPU temperature in idle state and maximum CPU temperature when the processor got overheated by special utilities:
Idle | Burn | |
Celeron D (Prescott) 2.8GHz | 45oC | 62oC |
Celeron (Northwood) 2.8CGHz | 32oC | 52oC |
Pentium 4 (Prescott) 2.8EGHz | 47oC | 66oC |
Pentium 4 (Northwood) 2.8CGHz | 34oC | 55oC |
The results hardly need any comments of ours. Prescott based processors warm up much more at work than their predecessors. This is now true for both: Pentium 4 and Celeron CPU families.
Now let’s see how big the overclocking potential of the new Celeron D processors is. Theoretically, the 90nm Prescott core features greater frequency potential, which makes Celeron D processors better overclockable than the older Celerons. On the other hand, these CPUs are based on Prescott C0 core stepping, which is used only in Pentium 4 processors with 3.4GHz frequency. However, we have already managed to easily overclock these processors up to 3.6GHz with simple air cooling involved. Celeron D generates less heat than Pentium 4 that is why it can turn out even better overclockable than the Pentium 4.
We had two Celeron D processors on Prescott core in our lab with the nominal frequencies of 2.66GHz and 2.8GHz. To study the frequency potential of the new processor family we decided to overclock both of them. However, during our overclocking experiments it turned out that the standard cooler shipped with Celeron D is too weak to ensure sufficient cooling for our testing participants. During work both overclocked Celeron processors got overheated real quick, which resulted in system instability. Therefore, if you are planning to per4form some Celeron D overclocking make sure that you have a good cooler at hand. During our tests we used one of the best air cooling solutions from Zalman – CNPS7000A-Cu.
The second thing worth mentioning is the fact that the maximum frequency these processors managed to reach during our overclocking experiments is highly dependent on the power voltage. In other words, by increasing Vcore above the nominal, which is 1.375V in our case, the stability threshold for the CPU got higher. This Prescott’s behavior is a direct opposite to what Northwood core did, when the overclocking results hardly got any better with the processor Vcore growth. That is why to achieve better results we increased Vcore up to 1.475V for our testing participants. This 7% Vcore growth gives us some hope that the processor resource will not get too much smaller and it will not die earlier than expected. The first one to go through our tests appeared Celeron D 335 processor with 2.8GHz clock frequency. Keeping in mind that the FSB frequency of this CPU is 133MHz, the multiplier should equal 21x. When we overclocked this processor, we managed to increase the FSB frequency to 170MHz without losing any of the system stability.
As a result, the CPU clock frequency grew up by the good 28% above the nominal and reached 3.57GHz. This is actually a pretty predictable outcome proving that the frequency potential of the Prescott C0 core stepping is about 3.6GHz.
The second CPU we overclocked, Celeron D 330, works at the nominal 2.66GHz and features 20x clock frequency multiplier. During overclocking all the conditions were the same as in the previous case, but we turned out to be luckier this time: we managed to increase the FSB frequency from the nominal 133MHz up to 190MHz.
As you see, the frequency of the overclocked Celeron D with the 2.66GHz clock rate grew up to 3.8GHz: the gain made 43%. This way, we can conclude that even among Celeron D Prescott with C0 core stepping there are highly overclockable pieces, which can contribute a lot to the overall system performance. To prove this statement of ours we have also included into the further performance analysis the results for the Celeron D 330 overclocked to 3.8GHz.
Our test session is aimed at finding out how fast the new budget Celeron D processors actually are. We tested both processor models we had at our disposal, that is 330 and 335 CPUs with 2.66GHz and 2.8GHz clock frequencies respectively. We will compared the performance of these solutions with the results shown by “old” Celeron processors on Northwood core with the 2.7GHz and 2.8GHz frequencies. Also, we included the results for the direct competitors of Intel Celeron D processors from the budget AMD CPU family, i.e. Athlon XP 2700+ and 2800+ selling at about the same price. Besides the above listed CPUs, we will also consider the results of a few Pentium 4 processors with 2.4GHz core clock rate.
Of course, we couldn’t help testing the Celeron D processor 2.66GHz overclocked to 3.8GHz, which may become an excellent overclocker’s choice if it shows adequate performance in benchmarks. And in order to be able to fairly evaluate the relative performance of this solution after overclocking, you can also see the numbers for Pentium 4 Prescott 2.8GHz and 3.2GHz as well as the numbers for Athlon XP 3200+ processors.
As a result our testbeds looked as follows:
The tests were run in Microsoft Windows XP SP1 OS with the DirectX 9.0b installed. The BIOS Setup of the mainboards used was configured for maximum performance.
I have to point out before we start that despite the fact that we test budget CPUs today, we assembled our systems from very expensive and high-quality components. Our choice is explained by the desire to eliminate the negative influence on the testing participants’ performance of all other factors. That is why we used mainboards with dual-channel memory controller and a pretty expensive ATI RADEON 9800 XT based graphics card.
We decided to start our test session with gaming applications, as most users are interested in the performance of their systems in this type of apps first hand.
All in all, the situation looks rather favorable for the new Celeron D processors. First of all, you notice a big gap between them and the previous generation Celeron processors on Northwood core working at the same clock frequency. In fact, there is nothing surprising about it. As we know, Prescott core itself cannot ensure a performance increase, however, Celeron D has one more important trump: faster system bus. It is exactly what determines a significant advantage of the new Celeron processors over the old ones. However at the same time, the small L2 cache of the new Celeron D processors doesn’t allow these CPUs to compete with fully-fledged Pentium 4 solutions: in most cases Celeron D with 2.8GHz core frequency falls behind Pentium 4 CPUs with 533MHz bus and 2.4GHz core clock rate.
As for the performance of the Celeron D processor overclocked to 3.8GHz, it looks much more impressive I should say. Almost everywhere this processor demonstrates results comparable with those of Pentium 4 on Prescott core and 3GHz frequency. The only exceptions to this rule are Ton Raider: The Angel of Darkness and Aquamark3 test. The reasons lie in the gaming engines architecture, as they can use Hyper-Threading technology, so that the CPUs supporting Hyper-Threading look evidently better in these tests than Celeron D with Hyper-Threading disabled on the hardware level.
Although the introduction of new processor models in the Intel budget CPU family raised the performance to new heights, they are still unable to compete successfully enough with the budget solutions from AMD. For example in games Celeron D 335 working at 2.8GHz lost to AMD Athlon XP 2800+ costing the same money almost in every benchmark. Overclocking helps improve the situation for Celeron D a little bit: when working at 3.8GHz, this processor manages to outpace Athlon XP 3200+ in half the tests.
All in all, despite the evident improvements Intel made to its budget solutions, AMD Athlon XP remain a better choice for gaming systems, even though the performance gap between them and the new Intel CPUs got somewhat smaller today.
PCMark04 shows us somewhat more optimistic results for the new Intel budget processors. Celeron D 335 appears faster than Athlon XP 2800+ and Pentium 4 2.4GHz with 533MHz bus. Celeron D 330 overclocked to 3.8GHz runs neck and neck with Pentium 4 3.2E.
The situation we observe in 3DMark 2001 SE is similar to what we have just seen in 3D games. 3DMark03 allows Celeron D to get somewhat closer to the top: here the 335 model performed almost as fast as Pentium 4 2.4A on Prescott core.
In our test session we used a new WebMark 2004 test. This benchmark measures the performance (response time) of the system during the browsing of various web-sites designed with different up-to-date Internet technologies and algorithms, such as Macromedia Flash, Shockwave, Javascript, Java, DHTML, SSL, NET, etc.
The performance of Celeron D working at 3.8GHz is beyond any possible limits. Due to high clock frequency this overclocked CPU outperforms even Pentium 4 3.2E GHz on Prescott core. As for the performance of the Celeron D processor at its nominal frequencies, it outpaces both Pentium 4 CPUs with 533MHz on Prescott and Northwood cores, but falls behind its competitor – AMD Athlon XP 2800+.
During the work of WinRAR archiving utility the enhanced data prefetch algorithm of the Prescott core appears very important. Moreover, larger L2 cache has also contributed to the pretty high performance of the new Celeron D processors. However, the available cache memory is still too small for the new CPUs to feel the real master of the situation. As a result, Pentium 4 processors look much better in WinRAR than Celeron D.
When we compress audio files in mp3 format, the size of the cache memory and the RAM performance hardly tell on the overall results at all. That is why such a high result of the Celeron D processor at its super high 3.8GHz clock frequency shouldn’t surprise you. When working at the nominal frequency, the new Celeron D manages to outperform the slower Pentium 4 models, but is still unable to compete with Athlon XP.
By the way, one more peculiarity of this test is the fact that the previous generation Celeron (Northwood) processors run faster than Celeron D on the Prescott core. So, it illustrates perfectly well that faster bus and larger cache memory is not a universal panacea against all problems caused by a longer pipeline of the 90nm core.
And during raw-video encoding into MPEG2 format, Celeron D proved highly efficient due to the SSE3 instructions support, as these particular instructions are actively used y the Mainconcept codec.
Celeron D processors also coped pretty well with the video encoding into MPEG4 format. In particular, Celeron D 335 working at its nominal frequency outperformed any Pentium 4 2.4GHz as well as Athlon XP 2800+. The overclocked Celeron D 330 working at 3.8GHz appeared even faster than Pentium 4 3.2E on Prescott core.
The budget CPUs are very unlikely to ever be used as a solution for professional workstations. That is why we will only run CineBench 2003 test here, which shows the performance of the tested systems during final rendering and during the work with OpenGL in a popular Cinema4D package.
In most cases, for example during final rendering, the absence of Hyper-Threading appears a weak spot of the Celeron D.
The transition of Intel’s budget processors to the 90nm Prescott core appeared a very successful move. SSE3 instructions support, larger 256KB L2 cache, and the use of faster 533MHz Quad Pumped Bus have increased the performance of this processor family really tangibly.
As we see, the new Celeron D processors turned 10-40% faster without any serious frequency increase. However, it is even more pleasing when you look at the prices. Celeron D processors based on Prescott core cost exactly as much as the previous generation Celeron processors on Northwood core working at the same frequencies. This way Intel increased the power of its budget solutions “absolutely for free”.
However, I would like to point out that the performance gain obtained by the new Celeron D processors is unfortunately too low for them to compete with the corresponding AMD Athlon XP solutions on equal terms. AMD processors selling at the same price are still faster, although not all the time and not that much faster now.
One more important thing resulting from the shift to a new 90nm Prescott core is the increased overclocking potential of the Celeron D processors. Our first overclocking experiments indicated that Celeron D processors can reach pretty high frequencies when overclocked. And the performance in this case appears comparable with that of the Pentium 4 3GHz, which is a pretty high achievement for a $100 CPU, I should say. Therefore, Celeron D processors should be much more beloved by overclocking fans than their Northwood based fellows.
In general, I have to admit that Celeron D is a pretty competitive CPU for low-cost PCs. This processor will become an excellent choice for many user’s out there.