Erm, I thought any old unlocked AMD chip could run at a 133 mhz bus speed, provided the motherboard supports the fsb. Like, say you took a Duron600@950 w/ a 9.5x100 and changed it to 933 (7x133.) Why is there a distinction (and a price difference) between these newer cpus? Thanks.
Difference between 200/266 fsb AMD cpus?
- Thread starter Mage
- Start date
nobody seems to know of any other difference... the price difference is for the uninformed or those who don't want to mess with the bridges
Yes, I'm curious about that myself. I've never overclocked before so I wondered the diff between the 2. I'm going to build a DDR 2100 so which should I go with? The 200mhz or the 266mhz? 
Well call me stupid (not really) but if DDR runs at double the FSB why would you need a 266mhz bus speed on the Thunderbird?
Demon-Xanth
Lifer
- Feb 15, 2000
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The same diff between 1.2GHz and 1GHz CPUs. Tolerence that they were tested to and how they are setup.
Demon-Xanth
Lifer
- Feb 15, 2000
- 20,551
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stupid(not really) 266 is double the FSB, and the higher the better. Speed GOOD!
btw, stupid(not really) is kind of a funny name.
btw, stupid(not really) is kind of a funny name.
Well I am a funny guy(funny haha, not funny queer). So the 266 is the DDR speed? There was about a $40-50 diff yesterday on the 266 and the 200 on pricewatch.com yesterday.
Umm...
Thanks for your replies, but still no real answer!
What is the difference between the cpus? Is there any reason to believe that the older (200) cpus CAN'T use the 133 mhz fsb? (That IS the fsb, considering you multiply the clock by either 100, 133, or whatever speed the mobo is.) Just what do the old cpus lack, and the new cpus have, that justifies this price difference, if both can do the same thing (run at 133 mhz fsb)?
Thanks for your replies, but still no real answer!
What is the difference between the cpus? Is there any reason to believe that the older (200) cpus CAN'T use the 133 mhz fsb? (That IS the fsb, considering you multiply the clock by either 100, 133, or whatever speed the mobo is.) Just what do the old cpus lack, and the new cpus have, that justifies this price difference, if both can do the same thing (run at 133 mhz fsb)?
the 100 fsb cpu will run on the 133fsb....either by o/c or change multiplier lower and going to 133
1200= 12x100 or 9x133
1200= 12x100 or 9x133
So basically a 266 fsb chip is just a chip that runs at 133 by default? It's multiplier default is lower?
After ton's of testing, I found the 133fsb speed, (266DDR), useless for me.
Currently running 112(224DDR)/37 x9=1008MHz. AGP and IDE(?) run at 75MHz.
Memory at HClk+PCICLK, or 149MHz.
Running 133(266DDR)/33 x7.5=998MHz. AGP and IDE run at 66MHz.
Memory is not given choice of HClk+PCIClk, and must run at 133MHz.
Also tried 140(280DDR)/35 x7=980MHz. No boot at x7.5 or 1050MHz.
AGP and IDE run at 70MHz. Memory stuck at 140MHz.
Benchmarks clearly show 112MHz x9 is fastest. The only thing 133MHz does is increase internal CPU speed, but slows down everything else. More is gained by increasing everything, not just internal CPU speed.
Currently running 112(224DDR)/37 x9=1008MHz. AGP and IDE(?) run at 75MHz.
Memory at HClk+PCICLK, or 149MHz.
Running 133(266DDR)/33 x7.5=998MHz. AGP and IDE run at 66MHz.
Memory is not given choice of HClk+PCIClk, and must run at 133MHz.
Also tried 140(280DDR)/35 x7=980MHz. No boot at x7.5 or 1050MHz.
AGP and IDE run at 70MHz. Memory stuck at 140MHz.
Benchmarks clearly show 112MHz x9 is fastest. The only thing 133MHz does is increase internal CPU speed, but slows down everything else. More is gained by increasing everything, not just internal CPU speed.
With the 266 FSB I saw almost 30MB/s increase on my hard drive speed in Norton System Works 2k1. That was on a WD ata 66 drive. IMO that's good.
Right on RobsTV, I glad someone finally brought up this point. I have a KT7 non A which is running on a 113fsb. That puts my RAM at about 151MHz and my PCI devices at 37.3MHz. I can't see any advantage to going to the KT133A chipset. I would have to run a 151MHz fsb to see the same boost for my RAM and PCI devices. Plus my T-bird 750 would be stuck at 6.5 x 151 for only 981MHz it is running 1017 now. 7 x 145 would be the only other choice and then the rest of my system would be slowed down. To make a long story short (too late I think) if your KT133 board can support a 110MHz fsb then don't waste your money on a KT133A!
HCLK is same as FSB.
PCICLK is same as PCI bus, usually 1/3 HCLK. AGP bus is 2x PCICLK.
Basic systems were designed to run at 100MHz FSB (HCLK), with PCI bus speed at 33MHz (PCICLK).
Then came PC133 memory. Some motherboards like Abit took adavantage of this new memory by allowing you to run the memory at FSB + PCI bus, or 100+33, or 133MHz. But, in actuality, most do not run FSB at 100Mhz, and in my case it is at 112MHz, which puts the PCI bus at 37MHz, so my Abit motherboard which allows HCLK+PCICLK at certain FSB speeds only, will run the memory at 149MHz in this case. Huge performance boost. Plus you get the performance boost on the overclocked PCI and AGP bus, which speeds up video and harddrives.
The new 133 FSB setting has a 1/4 PCICLK speed, to keep things at 33MHz. But, with that setting, you can only set memory at HCLK, or 133MHz. No option of HCLK+PCICLK, as that would be 166MHz.
PCICLK is same as PCI bus, usually 1/3 HCLK. AGP bus is 2x PCICLK.
Basic systems were designed to run at 100MHz FSB (HCLK), with PCI bus speed at 33MHz (PCICLK).
Then came PC133 memory. Some motherboards like Abit took adavantage of this new memory by allowing you to run the memory at FSB + PCI bus, or 100+33, or 133MHz. But, in actuality, most do not run FSB at 100Mhz, and in my case it is at 112MHz, which puts the PCI bus at 37MHz, so my Abit motherboard which allows HCLK+PCICLK at certain FSB speeds only, will run the memory at 149MHz in this case. Huge performance boost. Plus you get the performance boost on the overclocked PCI and AGP bus, which speeds up video and harddrives.
The new 133 FSB setting has a 1/4 PCICLK speed, to keep things at 33MHz. But, with that setting, you can only set memory at HCLK, or 133MHz. No option of HCLK+PCICLK, as that would be 166MHz.
Scabilion,
Norton benchmarks are awful, and should not be used to determine any benchmark whatsoever. If you truly want to measure your HD speed get HDTach or get a hold of Adaptec's ThreadMark.
Norton benchmarks are awful, and should not be used to determine any benchmark whatsoever. If you truly want to measure your HD speed get HDTach or get a hold of Adaptec's ThreadMark.
RobsTV, in your first post you gave 3 examples of memory speeds:
But if you're running DDR wouldn't that be
If you did use DDR, which type were you running: 1600 or 2100?
Thanks for the help
- 149
- 133
- 140
But if you're running DDR wouldn't that be
- 298
- 266
- 280
If you did use DDR, which type were you running: 1600 or 2100?
Thanks for the help
I think in unoverclcking only, the athlon-c 266 fsb or 133 ddr. 133 is the default speed for just the cpu the agp and pci cards are unoverclocked and in order to reach 133 on a AMD athlon-B you need to overclock the cards as well. I might be wrong?
Demon-Xanth
Lifer
- Feb 15, 2000
- 20,551
- 2
- 81
RobsTV: at 100-124MHz FSB AGPclk is 2/3 FSB clock and PCI is 1/3 (and often RAM is FSB+33). At 133 it goes to AGp= 1/2 and PCI=1/4 (and RAM is usually FSB speed). In many cases the latter is better because you are OCing the other components less and there is a smaller chance for them to cause instability.
Demon-Xanth wrote: "RobsTV: at 100-124MHz FSB AGPclk is 2/3 FSB clock and PCI is 1/3 (and often RAM is FSB+33)."
That is almost exactly what I said, except ram is not FSB+33, but rather FSB+PCICLK. If your running 112MHz, PCI clock is 37MHz, memory is NOT 112+33, but is instead 112+37, or 149MHz. With quality PC150 memory so cheap now, you would be doing a disservice to yourself by running it at anything less than 145MHz.
Also, AGP is 2X PCI + whatever you have AGP set for. For example, with AGP at 1X means 66Mhz with a FSB of 100 or 133, and 4x AGP would be 264Mhz in those cases. with 112MHz FSB, AGP at 1X would be 75MHz, and 4x would be 300Mhz.
I think most people that buy AMD's here will overclock. To overclock correctly means to find the best combination, by increasing everything as much as you can, then perhaps back it down a notch for stability. Increasing just 1 component, such as CPU, usually won't give you as much of a gain compared to increasing the CPU cache less, and increase everything else a little more as well. You can usually still run the CPU at the same end speed, using either 200MHz DDR or 266 MHz DDR, and perhaps a little higher using 200MHz DDR, just because of greater "usable" mulitpliers available at that speed. Every part in your system should be able to overclock by 10% to 20%, as quality control should assure us of that. Running 112MHz FSB is only overclocking your "entire" system 12%. (based on 100Mhz).
EmperorRob wrote: "If you did use DDR, which type were you running: 1600 or 2100?"
I am speaking of the new KT133A Vs KT133 boards. The "A" supports the new 133MHz FSB, 266MHz DDR, but not the new DDR memory, so memory is stuck at FSB or FSB+PCICLK option if FSB is less than 133MHz.
That is almost exactly what I said, except ram is not FSB+33, but rather FSB+PCICLK. If your running 112MHz, PCI clock is 37MHz, memory is NOT 112+33, but is instead 112+37, or 149MHz. With quality PC150 memory so cheap now, you would be doing a disservice to yourself by running it at anything less than 145MHz.
Also, AGP is 2X PCI + whatever you have AGP set for. For example, with AGP at 1X means 66Mhz with a FSB of 100 or 133, and 4x AGP would be 264Mhz in those cases. with 112MHz FSB, AGP at 1X would be 75MHz, and 4x would be 300Mhz.
I think most people that buy AMD's here will overclock. To overclock correctly means to find the best combination, by increasing everything as much as you can, then perhaps back it down a notch for stability. Increasing just 1 component, such as CPU, usually won't give you as much of a gain compared to increasing the CPU cache less, and increase everything else a little more as well. You can usually still run the CPU at the same end speed, using either 200MHz DDR or 266 MHz DDR, and perhaps a little higher using 200MHz DDR, just because of greater "usable" mulitpliers available at that speed. Every part in your system should be able to overclock by 10% to 20%, as quality control should assure us of that. Running 112MHz FSB is only overclocking your "entire" system 12%. (based on 100Mhz).
EmperorRob wrote: "If you did use DDR, which type were you running: 1600 or 2100?"
I am speaking of the new KT133A Vs KT133 boards. The "A" supports the new 133MHz FSB, 266MHz DDR, but not the new DDR memory, so memory is stuck at FSB or FSB+PCICLK option if FSB is less than 133MHz.
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