the speed technoz pentium II klamath review

The Intel Pentium II is a hell of a speed demons' CPU if only price wasn't a concern. Klamath is the name given to the initial batch of Pentium II series with speeds of 233, 266 and 300 MHz. All these chips have a 512KB Second Level Cache Memory (L2 Cache), run on a voltage of 2.8V and a Front-Side Bus (FSB) of 66MHz. Almost all of the new Klamath series are clock-locked, which means that you cannot increase the multiplier of the CPU beyond the rated FSB. Take for example a 233MHz processor which runs at 3.5 x 66MHz. It is impossible for you to over-clock it and still keep it running at 66MHz FSB just by merely increasing the multiplier from 3.5 to something higher. This means that the only way to clock the Klamath is to increase the FSB up to 75, 83, 92, 100, 103, 112 or even 133 MHz. It seems so easy and risk-free, but in fact it's not as easy as it sounds. Increasing the FSB also means that the PCI and AGP clocks also increase beyond their normal speed, and this spells disaster for your hard disk, graphic cards, soundcards and all other peripherals that runs on PCI or AGP bus. The table tabulated at the bottom right shows the PCI clock frequency at each respective FSB frequency.

FSB Freq. PCI Freq. 60.0 30.0 66.6 33.3 66.8 33.4 75.0 37.5 83.3 41.7 100.0 33.3 103.0 33.4 112.0 37.3 133.0 44.3

The official PCI clock frequency is 33.3MHz, and anything above that means that your PCI peripherals and hard drive are running beyond the rated safe frequency. At 37.4 to 37.5 MHz, it is still considered very safe except for the increased heat dissipation, but anything more than 40MHz would require some pretty good quality hardware and cooling apparatus.

The Klamath's L2 Cache, which runs at "half the clock speed", has a rating of 7Ns and a speed rating of 150MHz. This means that at 300MHz, this baby's L2 Cache is already running at the tip of the speed limit, so don't expect your CPU to be 100% crash proof at anything higher than that. The only difference that separates the 300MHz from its counterpart is the ECC (Error Correction) included in the L2 Cache, which is supposed to give some extra but unnecessary assurance to the L2 Cache running at 150MHz.

Over-clocking the Klamath

After that fast intro on the Klamath, let us see how we can set this chip on fire and really get it to run! All Klamath are pretty much the same, regardless of the rated clock speed, and as mentioned earlier, the only difference between them is the multiplier. In order to clock your 233 and 266 to a whopping 300MHz, you need to run it at either the 75 or 100MHz FSB. Although the Klamath is only rated at 66MHz FSB, it is definitely capable of running at 100, 112 and even 133MHz FSB without any problems. The 233MHz Klamath is definitely the best grab now since Intel's manufacturing yield is very high, and all 233s can be considered a 300MHz Klamath with a multiplier locked at 3.5, and also, almost all of the 233s can run at 300MHz without much problems. Only 1 to 2 % of the 233s might have some difficulty running at 300MHz, and these are probably the chips that failed the 300MHz Q/A test but which are at least definitely capable of running at a lower speed of 233MHz. The highest speed you can take a Klamath to is 336MHz (112 x 3) or 350MHz (100 x 3.5), but you risk running your L2 Cache above the rated safe speed. A 300MHz Klamath is pretty much of a "cash dumpling" (read: not worth the money) if you are one who goes all out in over-clocking, coz u you just simply cannot take it too far.

So let's get on to clocking the Pentium II 233MHz CPU. Since all 233 to 300 MHz Klamath chips run on 2.8V, it is no doubt that a 233 also runs safe and stable up to 309MHz at a

"..you can actually lower the voltage down to a lowest voltage of 2.6V for your Klamath 233MHz" -- speedz demon

Vcore Voltage of 2.8V. But to take it up to a speed of 336MHz, you will require a slightly higher voltage of at least 2.9V. It differs slightly, depending on your motherboard and on your CPU. And lastly, to take that 233MHz to a whopping speed of between 350 to 360.5 MHz, you will require at least a 3.0V. That is the bare minimum to run it stable. Do not ever try running at 350MHz below 3.0V, or you will get lots of O/S and I/O problems and sometimes hard disk crashes, which actually happened to me. All Klamath chips can take a maximum voltage of 3.2V, even though the actual recommended voltage according to Intel's specifications is around 5% off the official 2.8V. Changing the voltage seems to be a very sensitive issue, but it is definitely a good way to get those unstable over-clocked CPUs running well. The main problem with raising the voltage, as everyone knows, is the heat issue. Do NOT, and I emphasize again, do NOT, try to increase the voltage of your Klamath chip if you are still using the original heatsink and fan that comes with the chip, coz the cooling is simply insufficient. A non-over-clocked Klamath 300MHz runs really hot with the original heatsink and fan from Intel. There are some pretty good cooling systems out there, if you know where to find it in Singapore. I'll discuss this issue in another article on Speed-Coolingz! Here's a little tip for the non-over-clockers. Running a 233MHz at normal speed at 2.8V is probably already generating too much heat. If your motherboard supports manual setting for voltages (like the Abit BX6 motherboard), you can actually lower the voltage down to a lowest voltage of 2.6V for your Klamath 233MHz. It has been proven, and I used to be running at 2.6V at 233MHz with mine. This will greatly reduce the heat generation of the CPU.

Clock Speed Vcore Voltage 233 - 309 MHz 2.8v 336 MHz 2.9 or 3.0v 350 - 360.5 MHz 3.0 or 3.1v

Other than your voltage problems, some of you might have problems with your SDRAM because not all SDRAM can support the 100MHz and the 112MHz Front-Side Bus. One important point to note is that not all PC-100 MHz SDRAM modules can run at 112MHz. In fact only a few good brands can support 112 MHz and even fewer support 133MHz. As far as my knowledge goes, almost all 8Ns SDRAM can support 100MHz FSB, and these normally come as the PC-100 SDRAM that you find on the market now. Some of these PC-100 SDRAM, especially those manufactured by Hyundai, use 10Ns SDRAM instead of the usual 8Ns. Even at a higher rating, they can still run stable at 100MHz due to the higher quality of the module, but never ever expect it to be stable at 112 or 133 MHz. I heard from some local users on the Internet that there are 7Ns SDRAM modules in the market now, under the LGS (GoldStar) brand. There is a great misinterpretation regarding the LGS PC-100 SDRAM module, which I shall clarify here. LGS PC-100 SDRAM comes in 3 different models, and each using a different chipset for the SDRAM. Refer to the following table.

LGS SDRAM Marking Maximum FSB 7J (CAS 3) 100mhz 7K (CAS 2) High chance at 112mhz 8 (CAS 2) up to 125mhz

The 7J and 7K markings you find on those LGS PC-100 SDRAM modules do not mean that they are 7Ns SDRAM (I confirmed it on the LGS website myself). From my knowledge, the Samsung (SEC) PC-100 SDRAM are also not capable of running stable at 112MHz, as the ones found in Singapore all have a CAS rating of 3, with a SDRAM marking of -GL. You will require modules from Samsung that have the -GH or -G8 marking to get it running stable at 112MHz. So what are the SDRAM that can run stable at 112MHz? It has a lot to do with the CAS ratings on the ram-chips itself. For an SDRAM module to be 122MHz-capable, it has to be at least 8Ns with a CAS rating of 2 at 100MHz. And by setting the CAS rating to 3 in the BIOS, you will most probably get it running at 112MHz without many problems. There are some brands out there, namely Kingston and Unigen, that might be capable of running at 112MHz, but they cost much more (at least double) than the normal PC-100 Samsung, LGS, or Mitsubishi SDRAM that you can find. But do not despair! I bought my SDRAM locally and I have managed to run it at 112MHz without any problems. These are PC-100 SDRAM with a marking of TI and either -8 or -8A. TI stands for Texas Instruments, and I did a check on the RAM modules specification sheet from their website to confirm that the chips are rated 8Ns and have a CAS rating of 2 at 100MHz which satisfy the minimum requirements for a 112MHz FSB. In fact Texas Instruments even stated that it supports up to 125MHz with CAS set to 3. It seems to me that everyone is running short of TI PC-100 SDRAM, since I could not get anymore locally, unless some supplier is willing to bring in more of it. Since these chips seem to be assembled in Singapore, it shouldn't be much of a problem to do so. The pricing of the Texas Instruments SDRAM is about the same as the Samsung and Mitsubishi SDRAM, and it is definitely the best buy if you are interested in running your CPU at 112MHz.

So after you get that baby running at the desired speed, it is time to test the stability of the over-clocked CPU. I read from some other Internet sites that some people test the stability of the CPU by running a lot of programs concurrently, one of which is the Quake II demo. That is a pretty good idea, but here's a better one! The newly released game called "UNREAL" is a game very sensitive to over-clocked CPUs and Voodoo cards. This game truly utilizes every single processing power your CPU has and this really is a good test of stability. First, start your Word 97, follow by Excel 97, and lastly Outlook 97/98, and with all these windows minimized, start UNREAL. Play the game as usual, and if everything goes smoothly enough, you can be sure that your baby is running fast, smooth and stable.

Benchmark Comparisons

Enough of talk, now let's get down to benchmarking the over-clocked CPU. Here, we used 2 different programs for the testing and comparison of the CPU's speed, namely Winbench 98 and Wintune 97. A test on Quake II is also done, as it is the game that is most sensitive to changes in CPU speed. All the charts are self-explanatory, and the higher the value, the faster and thus better. Results tabulated here may vary slightly from any test results you might have obtained personally, and this is mostly due to the difference in hardware configuration. These benchmarks only serve as a gauge for comparison.

• WinBench 98 CPUmark32
  
• WinBench 98 FPUmark
  
• WinTune 97 Dhrystone
  
• WinTune 97 Whetstone
  
• Quake II Timedemo 1