Краткое содержание статьи: Intel's 815 chipset is not able to outperform the good old BX, but it certainly gives you a better margin for overclocking. Is it worth it?
Leading by Speeding: Solano at 166 MHz
BX Outclocked: Solano Shows Its Potential
The most significant characteristic of high performance computers is a fast system speed. This external clock speed (currently 133 MHz) is crucial for best overall performance still today. Some months ago, we had a VIA 694X and a Intel 440BX platform running at 150 MHz system speed and circumstanciated the performance gains thanks to the higher memory bandwidth. The results clearly indicate that raising the system speed is often more effective than obtaining a faster clocked processor.
Naturally I wanted to determine the performance benefit at 166 MHz Front Side Bus. So far there is no 815-166 (see picture). However, modern mainboards like the Asus CUSL2 support several clock speeds beyond the specified 133 MHz.
Maybe you are disappointed to hear that speeds faster than 166 MHz are not really possible today. Even with highest quality memory modules it is virtually impossible to run the system bus at any higher clock speed.
Demands: AGP
In contrast to the aged BX chipset, Intel's 815 has been designed for 133 MHz operation. As a result it comprehends all dividers in order to run the AGP within the specs (66 MHz). Remember that both the PCI and the AGP clock are derivated from the system clock speed. As the BX is approved for 100 MHz max, it only knows the dividers 1/1 and 2/3 (for 66 resp. 100 MHz FSB). Overclocked to 133 MHz, the AGP will run at 89 MHz - too much for many graphics cards!
This issue it even more critical at 150 MHz system speed: In this case, your graphics card has to endure 100 MHz (!) AGP speed, which is merely tolerated by GeForce models so far.
The Solano does not suffer from such problems, as the AGP speed does "only" reach 83 MHz even at 166 MHz system clock speed (divider 1/2). According to our experience, this is no problem for the majority of today's AGP graphics cards.
Demands: PCI and On-Board Components
The whole thing is a bit touchier for PCI components, as the bus will be running at 42 MHz. Timing critical add-on cards like SCSI or network controllers will easily be affected by high overclocking, thus you can almost be sure of running into trouble.
For performance freaks, there is only one way of solving this: Get rid of any hardware which you do not require. That will reduce the number of PCI cards to one or two (sound card and modem/network).
If you depend on specific components, I would stop thinking about 166 MHz FSB right now. The following hardware can cause problems:
SCSI adapters
IDE-RAID controllers
100Base-TX- or ATM network adapters
Firewire controllers
High end audio devices
Any exotic hardware
Demands: The CPU
Every Pentium III will work reliable at 166 MHz as long as the core clock does not reach lunatic speeds. Using a 166 MHz setup, a Pentium III 650/100 would have to run at 1083 MHz, for example. You certainly do not need to have visionary power to realize that there's no point of even trying it.
It's best to use a 133 MHz model for overclocking to 166 (Pentium III 600EB, 667, 733, 800EB, etc). The next table discerns between realistic setups and desperate configurations:
CPU
Specs
Core speed at 166 MHz FSB
Chance of success
Core voltage
Pentium III 550E
100 x 5.5
916 MHz
Little
1.75 - 1.8 V
Pentium III 600E
100 x 6
1000 MHz
Hardly any
1.75 - 1.85 V
Pentium III 600 EB
133 x 4.5
750 MHz
Excellent
1.65 - 1.75 V
Pentium III 650
100 x 6.5
1083 MHz
No chance
-
Pentium III 667
133 x 5
833 MHz
Good
1.65 - 1.75 V
Pentium III 700
100 x 7
1166 MHz
No chance
-
Pentium III 733
133 x 5.5
916 MHz
Good
1.7 - 1.8 V
Pentium III 750
100 x 7.5
1250 MHz
No chance
-
Pentium III 800 E
100 x 8
1333 MHz
No chance
-
Pentium III 800 EB
133 x 6
1000 MHz
Fair
1.75 - 1.85 V
Pentium III 850
100 x 8.5
1416 MHz
No chance
-
Pentium III 866
133 x 6.5
1083 MHz
Hardly any
1.75 - 1.9 V
Pentium III 933
133 x 7
1166 MHz
No chance
-
Pentium III 1000
133 x 7.5
1250 MHz
No chance
-
Demands: SDRAM
Though most PC133 SDRAM modules run stable at this clock speed, they usually cannot be operated at a CAS latency of 2 clock cycles. Many types have to be run at CAS 3, which reduces the system performance by few per cent. At first sight, it does not sound much, but remember that the difference between two processor speed grades (e.g. PIII 650 and 700) is usually about the same!
We have always been using highest quality SDRAM memory from Micron/Crucial, Memory Solutions or Wichmann Workx (Germany), which can be operated at CAS 2. Even when "only" running 150 MHz you may be forced to reduce the CAS latency time from 2 to 3 clock cycles. At 166 MHz, not even one of our different memory modules runs stable at CAS 2.
Well, I think you understand what I am figuring out right now. If an average SDRAM module can only be run at 133 MHz using CAS 3, the timing would have to be increased even more at higher clock speeds, which of course is impossible. Thus forget CL3 SDRAM for this undertaking.
In order to have the system running stable, I had to reduce all SDRAM timings to the slowest options: CAS 2, RAS-to-CAS 3 and Precharge Time 3.
Asus CUSL2
I had two interesting motherboards available for this project: AOpen AX3S Pro and the Asus CUSL2. The Asus finally made it, because the AOpen board operates the main memory at only 140 MHz when running 166 MHz FSB due to some limitation of its clock generator. A comprehensive 815 motherboard round up is scheduled for the next weeks. Than we will also introduce the AX3S Pro in detail.
The CUSL2 is a typical Asus motherboard as it gives you excellent quality teamed with performance and overclocking features. Making use of the ICH2 chip, the two IDE ports are UltraATA-100 compliant. Six PCI slots, AGP 4x and the AMR slot are provided.
The system did not want to run stable at 166 MHz FSB when I installed more than one memory module. Obviously the timing is already at the limit using one module.
Test configuration
Test system
CPU
Several Intel Pentium III CPUs
Motherboard
Asus CUSL2, Intel 815 Chipsatz
RAM
128 MB PC133 SDRAM, 7ns (Crucial/Micron or Wichmann Workx). CL3 at 166 MHz
Asus V6600, nVIDIA GeForce 256 32 MByte SDRAM nVIDIA Drivers 5.08 for Windows 98
OS
Windows 98 SE 4.10.2222 A
Benchmarks and Setup
Office Application
BAPCo SYSmark2000
OpenGL Game-Benchmark
Quake III Arena Retail Version command line = +set cd_nocd 1 +set s_initsound 0 Graphics detail set to 'Normal', 640x480x16 Benchmark using 'Q3DEMO1'
Direct3D Game-Benchmark
Expendable Downloadable Demo Version command line = -timedemo 640x480x16
Screen Resolution
1024x768x85, 16 Bit
DirectX-Version
7.0a
As already mentioned above, I had to reduce all SDRAM timings to the slowest settings in order to ensure system stability. Again, I used the Asus V6600 GeForce graphics card with SDR memory, so that the benchmark results can still be compared to all the preceding articles:
In spite of the slow memory timings I had to use at 166 MHz, SYSmark was still scoring better than at 133 MHz. Of course it's quite senseless to overclock your system to 166 MHz only for office applications. Let's take a look at the game benchmarks.
Benchmarks: Expendable Timedemo
Just as we expected, a 166 MHz system is ahead 133 MHz configurations at the same core clock speed. But the distance is not ample at all.
Benchmarks: Quake III Arena
First of all, this results proves again that Quake III is one of the very best allround benchmarks, as all computer components are important for it. Quake III will run more than one CPU speed grade faster on a 166 MHz system.
Conclusion
This time, Solano showed its real potential. Despite the restraining memory timings, the higher clock speed shows an impact. But to be honest, you really have to ask yourself if the effort is worth it, as most PCI cards likely have to be abandoned.
Your software definitely runs faster, but getting SDRAM which really is reliable at 166 MHz could become tough. Actually, overclocking to 166 MHz is likely to become an ordeal due to frequent hang ups caused by inadequate memory. In addition, your PCI components will have to tolerate 42 MHz bus clock.
Last but not least it could become necessary to increase the CPU core voltage in order to make the overclocked system more stable. As you can imagine, this measure does not contribute to system stability as long as you are still playing around.
On the other hand, there are high Quake III results which may tempt one to try it, as the performance gains are quite remarkable. At only 666 MHz core speed, the 166 MHz system performs just like a Pentium III 800/133. To achieve GHz-performance, you only need to overclock a Pentium III 733 to 917 MHz at 166 MHz FSB.
История мейнфреймов: от Harvard Mark I до System z10 EC Верите вы или нет, но были времена, когда компьютеры занимали целые комнаты. Сегодня вы работаете за небольшим персональным компьютером, но когда-то о таком можно было только мечтать. Предлагаем окунуться в историю и познакомиться с самыми знаковыми мейнфреймами за последние десятилетия.
Пятнадцать процессоров Intel x86, вошедших в историю Компания Intel выпустила за годы существования немало процессоров x86, начиная с эпохи расцвета ПК, но не все из них оставили незабываемый след в истории. В нашей первой статье цикла мы рассмотрим пятнадцать наиболее любопытных и памятных процессоров Intel, от 8086 до Core 2 Duo.