what the deal with FSB's?

[Jeff Bolton]

ok i didn't know where to put this so i'll just put it in intel since it pertains more to this brand.

one of my friends has a dell w/P4 1.3 ghz processor. i have athlon t'bird 1.2 ghz overclocked to 1.33 ghz. i keep telling him that mine is faster (even if it wasn't a proven fact that athlon performs better than higher clocked P4's, i still have a 33mhz advantage on him), but he doens't really believe me. he'll admit a little bit, but then he's like "but I have a 400mhz FSB!!" i'm like big whoop.

my question is this: i know that there has to be some difference in the way that the P4's FSB is set up...because i know that it isn't that AMD just doens't know how to make a 400FSB cpu...so can someone tell me...what's the difference between 266FSB athlons and 400FSB P4's. is it really 400mhz and just can't perform as well as a lower clocked AMD? i'd like to know!

thanks,

jeff

[Yodums]

Heh well for one you can tell him to get Sandra tell him to tell you the results etc.

The 400System Bus doesn't really mean much just tell him that his system bus is twice as much, his system must be twice expensive and yours still beats him in benchmarks so guess what you get the bang of the buck!

[ol' man]

Just tell him big deal if he has a higher FSB, his IPC sucks. Tell him in one cycle you can do 30% more intructions.

[batboy]

The P-4 has a quad pumped bus that is mainly to run the RAM faster. Unfortunately for him, your AMD "probably" beats his P-4 in most benchmarks, but like was said, download SiSoft Sandra and do a runoff to be sure. Now if he could overclock that P-4, that might even up things a bit.

[Jeff Bolton]

thanks for the input :) but you still didn't really anwer my question :(. any more input? i want to install sandra on his box next time i'm at his school...

here's my results..i was hoping that i could choose a P4 1.3 as one of my reference compters but it didn't work...but i still almost whip a 1.6 :) doesn't make sense that the real 1.33 has a bit higher benchy's though...strange

jeff

[Jeff Bolton]

Originally posted by batboy
The P-4 has a quad pumped bus that is mainly to run the RAM faster. Unfortunately for him, your AMD "probably" beats his P-4 in most benchmarks, but like was said, download SiSoft Sandra and do a runoff to be sure. Now if he could overclock that P-4, that might even up things a bit.

also, what does a quad pumped bus entail?

i want to learn, even if it is about a processor i'm not fond of :D

jeff

[Yodums]

Originally posted by Spike Spiegel


also, what does a quad pumped bus entail?

i want to learn, even if it is about a processor i'm not fond of :D

jeff

Nice benchmarks.

Quad Pumped Bus I'm guessing meaning, quad equvilent to 4 so 400 System Bus.

[Jeff Bolton]

so does that mean in essence the P4 bus speed is only 100mhz? that doesn't sound right either.

jeff

[Godfodda]

Originally posted by Spike Spiegel
so does that mean in essence the P4 bus speed is only 100mhz? that doesn't sound right either.

jeff

I think this is right. P4 is 4x100 where yours is 2x133. Someone using these will jump in shortly to verify, I'm sure.

[CrystalMethod]

No, that's exactly right. 100mhz FSB bus, but run in quad. Intel realized (probably too late), that CPU's in the Ghz range don't provide as much performance as they thought they would, over the competition.

[Jeff Bolton]

so what does this mean? i know it's always going to be a matter of debate, but does this mean a 2x133 FSB is better than a 4x100? i just want to know what i'm talking about next time i tell my friend what's up. :D

jeff

[Jeff Bolton]

and also if i'm correct PIII's are 1xABC (ABC being whatever their bus is) right?

jeff

[CrystalMethod]

Correct. Intels have a locked multiplier.
Example: My Celeron 800 has a 100 Mhz FSB. 8 X 100. The multiplier can't be changed no matter what your BIOS tells you, so increasing the multiplier doesn't do anything. An 800 Celeron at 10 X 100 FSB will still only yield 800Mhz. I can however increase the FSB, pushing closer to the chip's actual limit. Mine so far is a FSB of 125Mhz with stock Vcore. My current MB's BIOS doesn't allow for Vcore adjustment. I'm sure you know already know how increasing the Vcore affects stability for overclocked CPU's.

[Jeff Bolton]

yeah, as the chip gets faster it needs more power, and if the power ain't there, it doesn't work like it should.

jeff

[batboy]

The 1.3 gig P-4 runs at a FSB of 100 with a 13X multiplier which equals 1300 MHz, but the RDRAM memory bus is quad pumped which equals 400 MHz. The current P-4's can't completely utilize this extra memory bandwidth and memory speed yet, but the new Northwood P-4's should be able to. I'm oversimplifying it a little. Go to tomshardware.com and look in the CPU section for an article that should explain all of the technicalities better.

[Jeff Bolton]

thanks alot :)

jeff