# IDE Bus speed, and the kernel

## mrhodes

Hey everyone...

   I have a quick question about the ide bus speed.  When booting off the Livecd, I noticed that one of the messages says 'Assuming 33Mhz bus speed'   It said that I can change that by including "idebus=xx" in the kernel options....

However, I'm not sure eactly what to put there.... is it the FSB it wants? if so, I guess I would add 'idebus=266' to the kernel line.  Is this correct??

Thanks

Mike

----------

## AlterEgo

It's about yout PCI bus speed.

It's supposed to be 33 Mhz. So leave it (or seek the adventure)

----------

## mrhodes

you sure it's that slow???  33Mhz seems pretty slow.. I have a pretty fast computer, I don't think anything on my system is 33Mhz....

Isn't the Front Side Bus the same as the PCI bus...?  I thought they were all the same...

Mike

----------

## AlterEgo

yes I'm 100% sure

PCI should be 33 Mhz; AGP 66 Mhz

FSB depends on your processor: 66/100/133 Mhz

mem: depends om mem: 66/100/133/166 (except RDRam)

(x86 only)

But feel free to try   :Twisted Evil: 

----------

## mrhodes

Ok, 

thanks for the help  :Smile: 

I'll leave it as is

Mike

----------

## maxmc

What?

I set mine to 66. I have 133Mhz buss on my system and I had

to pass 66 to the kernel since my disks where running slow when my motherboard wasn't supported.. now it is so I run 100Mhz on the harddrives.

----------

## aardvark

 *maxmc wrote:*   

> What?
> 
> I set mine to 66. I have 133Mhz buss on my system and I had
> 
> to pass 66 to the kernel since my disks where running slow when my motherboard wasn't supported.. now it is so I run 100Mhz on the harddrives.

 

Ahem , are you talking about the Mhz of the PCI bus or the speed (grade) of your IDE controller. Sure , your, ide may be 133(?), but that is not Mhz but Mbyte/sec. As most (modern) harddisks are a.t.m physically no faster than 45 MB/s in the case of sequential reading of data (when does that  happen..). A ide transferrate of 66MB/s seems still enough.... Only if your harddisk has a very large buffer it may be useful for it to be able to empty it's buffer at a higher speed, say 133 MB/s, but situations where this will really help are rare.

BTW , afaik there is 66 Mhz PCI, but its quite special and the slots are different, and you're not likely to find it in normal desktop systems.

----------

## maxmc

 *aardvark wrote:*   

> 
> 
> Ahem , are you talking about the Mhz of the PCI bus or the speed (grade) of your IDE controller. Sure , your, ide may be 133(?), but that is not Mhz but Mbyte/sec. As most (modern) harddisks are a.t.m physically no faster than 45 MB/s in the case of sequential reading of data (when does that  happen..). A ide transferrate of 66MB/s seems still enough.... Only if your harddisk has a very large buffer it may be useful for it to be able to empty it's buffer at a higher speed, say 133 MB/s, but situations where this will really help are rare.
> 
> BTW , afaik there is 66 Mhz PCI, but its quite special and the slots are different, and you're not likely to find it in normal desktop systems.

 

Ok it might not be the same but it helped my HDD performance to set it to 66Mhz. And since nothing complains I might want to run it in 66Mhz...

I have one of the newset motherboards from Asus and they should support it.

----------

## col

only high end server type motherboards carry PCI 66 mhz slots....the slot & cards are different so unless you have these slots then you should leave it ar 33mhz. Generally pci devices can go a little higher (say 38mhz) but it is overclocking your pci devices & will end up causing problems.

----------

