why can amd users get over 200fsb speeds but intel users cant?

[drewthomas14]

i see amd users getting 200+fsb speeds but i dont see any intel users getting that high.

 

[lightbulb8817]

They have an unlocked mult. They can lower the mult. really low. You can't do that with a P4.

 

[drewthomas14]

duhhhhhhhh. why didnt i think of that. thanks. i remember some guy in here had an unlocked p4 and was running insane fsb speeds. i think his name is hippro or sumthing like that.

 

[NookieN]

As lightbulb said, multiplier lock is the main reason.

Another problem is that the P4 bus sends 4 data signals every clock cycle, whereas the Athlon's bus does 2. At 200Mhz you would have 800 megatransfers per second. Although that's possible, you'd probably get signal degradation in all but the newest, good quality boards.

And of course there's no real reason do to it. AMD users raise their fsb to 200 so they can run in sync with 400Mhz DDR. With a P4, a 133Mhz fsb has more bandwidth than 400Mhz DDR can fill. A 200Mhz fsb would be overkill to say the least. Once dual channel DDR comes out, that story may change.

 

[oops]

duhhhhhhhh. why didnt i think of that. thanks. i remember some guy in here had an unlocked p4 and was running insane fsb speeds. i think his name is hippro or sumthing like that.

I remember that was an engineering sample chip, those ones are unlocked.

 

[TUK101]

As lightbulb said, multiplier lock is the main reason.

Another problem is that the P4 bus sends 4 data signals every clock cycle, whereas the Athlon's bus does 2. At 200Mhz you would have 800 megatransfers per second. Although that's possible, you'd probably get signal degradation in all but the newest, good quality boards.

And of course there's no real reason do to it. AMD users raise their fsb to 200 so they can run in sync with 400Mhz DDR. With a P4, a 133Mhz fsb has more bandwidth than 400Mhz DDR can fill. A 200Mhz fsb would be overkill to say the least. Once dual channel DDR comes out, that story may change.

THis is the reason that Intel chips can hit much higher speeds in mhz than amd chips can. The wider pipeline allows for higher clock speeds. I dont know why this is, but that is what I read in some in one of my magazines lol.

 

[NookieN]

THis is the reason that Intel chips can hit much higher speeds in mhz than amd chips can. The wider pipeline allows for higher clock speeds. I dont know why this is, but that is what I read in some in one of my magazines lol.

That's true, but pipeline refers to the number of stages an instruction is broken up into as it is executed inside the chip. The speed of the frontside bus doesn't have much impact on the chip speed, but if the core/bus ratio is too high the chip will waste a lot of cycles just waiting for data in the ram.