133 mhz fsb??

[Chau]

i have a 1.4 ghz amd athlon and i thought it was 266 mhz fsb, but i checked 3d benchmark 2001 and under system info it said "internal clock 133 mhz"? any other way i can check it?

thanks

 

[kpxgq]

133mhz=266mhz ddr

 

[spanky]

becuz of ddr.... 133mhz x 2 = 266

 

[Chau]

is there any site that explain this in detail? or can anyone please explain this to me? I dont really understand..so what about if its a 1.4 ghz w/ 133 mhz fsb, would it show up as 66.5 mhz or something?

 

[pillage2001]

Actually, it's because of the EV6 bus??

 

[Shooters]

When people say that Athlons have a 266MHz FSB, it's misleading. The FSB runs at 133MHz.....or 133 million clock pulses per second. However, unlike other cpus, say the Pentium III, which transfers data only on the rising edge of the clock pulse, the Athlon transfers data on the rising AND falling edge of the clock pulse effectively doubling your bandwidth. Regardless, the FSB is still only running at 133MHz. People just say 266MHz to emphsize the fact that you're getting the equivalent bandwidth of a 266MHz single data rate FSB.

 

[Chau]

<< When people say that Athlons have a 266MHz FSB, it's misleading. The FSB runs at 133MHz.....or 133 million clock pulses per second. However, unlike other cpus, say the Pentium III, which transfers data only on the rising edge of the clock pulse, the Athlon transfers data on the rising AND falling edge of the clock pulse effectively doubling your bandwidth. Regardless, the FSB is still only running at 133MHz. People just say 266MHz to emphsize the fact that you're getting the equivalent bandwidth of a 266MHz single data rate FSB. >>



ohh ok thanks, i get it now

 

[HonkeyDonk]

<< When people say that Athlons have a 266MHz FSB, it's misleading. The FSB runs at 133MHz.....or 133 million clock pulses per second. However, unlike other cpus, say the Pentium III, which transfers data only on the rising edge of the clock pulse, the Athlon transfers data on the rising AND falling edge of the clock pulse effectively doubling your bandwidth. Regardless, the FSB is still only running at 133MHz. People just say 266MHz to emphsize the fact that you're getting the equivalent bandwidth of a 266MHz single data rate FSB. >>



well said.

 

[spanky]

<< is there any site that explain this in detail? or can anyone please explain this to me? I dont really understand..so what about if its a 1.4 ghz w/ 133 mhz fsb, would it show up as 66.5 mhz or something? >>




ddr starts at 200mhz. a 1.4 tbird w/133fsb is prolly using sdram...in which case it would be just as advertised...133mhz.

 

[cuteybunny]

so whats with seller advertising duron as 200 FSB whether its using sdram or ddr?
isnt that marketing bluff to sell whatever they claim it to be. so a PIV using SDRAM will be 100FSB not 400 FSB as they claim it to be. so all one need to do is increase memory bandwidth then say it 300fsb 400fsb whatever bs, the techie know but the average folk would not know the difference or is confused.

 

[spanky]

cutebunny: i guess. but then u can say the same about all previous generation cpus. the pentiumII's began advertising they were 100mhz fsb, but if u had only pc66 ram, u would have to "underclock".

 

[Soybomb]

<< the pentiumII's began advertising they were 100mhz fsb, but if u had only pc66 ram, u would have to "underclock >>


Okay I never had a great grasp on how amd classified fsb speeds, but you just lost me here.
So the P2 at 100fsb's were multiplier locked....meaning you could only change fsb speeds. So if a 500 was locked in at a multiplier of 5 and you had to run a 66mhz bus you'd only have a 330mhz computer. This isn't really anything to blame intel for, just the customer for being dumb.

So now lets say I take a 1.4tbird that is the 266mhz fsb. In reality, its never running 266 mhz on the bus right? It was my understanding that everything ran at 133mhz, but the ram (assuming DDR) could send/recieve on the trailing edge of each clock cycle as well as the leading edge. So in essence the 266 isn't truly representative of whats going on but just teh ddr function.

To me this means that the intel processors could always run at what they were rated to, while an amd can never truly run at a 266 fsb speed, but 133 with ddr functions (assuming no OC, etc)

Or do I have it all wrong?

 

[spanky]

the point is that the cpu manufacturers are not really falsely advertising. if a consumer chooses to run the cpu at a lower speed, it is not the cpu manufacturer's fault.

 

[Shooters]

It isn't false advertising or misleading. You guys are getting the FSB and the memory bus confused with eachother. They ARE NOT the same thing. You have to realize that FSB is the speed at which the cpu communicates with the system memory and the memory bus is the speed at which your memory is actually running. It just so happens that many mobo manufacturers make their boards so that the FSB and memory bus run synchronously (at the same speed), which is probably the cause of this confusion, but there are some boards that allow you to run the FSB and memory bus asynchronously (at different speeds). For example, Durons have a FSB of 100MHz, but you get the effective bandwidth of a single data rate 200MHz FSB care of the ev6 bus mentioned earlier. Even though the FSB is only 100MHz, some mobos out there let you run the memory bus at 133MHz should you happen to have PC133 memory. Therefore the FSB is running at 100MHz (or effectively 200MHz depending on how to care to look at it) but the memory bus is running at 133MHz.

Another example, I have a 1333MHz Thunderbird with a 133MHz FSB (effectively 266MHz) with PC133 SDRAM. If I were to switch to PC2100 DDR RAM my FSB would still be running at 133MHz (once again 266MHz effective because of the ev6 bus). Switching to DDR RAM would only change the bandwidth of the memory bus, not the FSB.

Basically what I'm saying is that the FSB of a cpu does not change just because you use a different type of RAM. The only way a FSB is going to change is if you physically change it yourself (i.e. overclocking and underclocking); its speed is not dictated by the speed of the RAM. Remember they are two different buses. Changing to a different speed or type of RAM only changes the speed and/or bandwidth of the memory bus; it will not affect the speed and/or bandwidth of the FSB.