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PCI lock - always good?

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Anonymous
a b K Overclocking
November 20, 2004 8:41:36 PM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

PCI lock is getting a lot of attention here the last couple of weeks. I'd
like to know more about it, with regards to some of the mobo/cpu combos
people are using lately. I have not used any Semprons or 64s; all the
machines I'm building are still based on the 2500+, usually the mobile
version and an NF-7/7S. I'm running the mobiles at 2.2 with multiplier
increases - rarely do I mess with clients' machines FSB. On my main machine
I've tried various things, and my NF-7 has PCI lock.

My question is, with the various FSB speeds possible, is PCI lock always
advisable, and what about AGP lock? I used to have to worry about that, but
I don't see much press on it right now.

thanks,

jakesnake

More about : pci lock good

Anonymous
a b K Overclocking
November 20, 2004 10:20:33 PM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

On Sat, 20 Nov 2004 17:41:36 +0000, jakesnake66 wrote:

> My question is, with the various FSB speeds possible, is PCI lock always
> advisable, and what about AGP lock? I used to have to worry about that, but
> I don't see much press on it right now.
>
The nominal pci bus speed is 33.33Mhz, and double that for thre nominal
AGP bus speed. normally, the AGP bus is derived from just doubling the
PCI bus speed so if It's locked Then they both should stay in spec. if one
never changes the FSB speed, or keeps it on 33MHz boundaries then a pCI
lock really serves no purpose. Go outside the 33MHz boudaries on the FSB
and you may end up putting the PCI/AGP buses too far over spec for the
PCI/AGP devices to operate properly. Before the PCI lock, the other buses
were derived from dividers. For instance, with a FSB of 100MHz a divider
of 3 was used for the PCI bus, and the pci bus was doubled. This sets the
pci and agp buses in spec. Now if you raise the FSB to 133 and don't
change the 3 divider, well, you end up with a PCI bus speed of 44.4MHz and
an AGP bus speed of 88.8MHz. You'd be hard pressed to find any pci device
that will run reliably over 40MHz. So at 133 Mhz a 4 diver is used, and at
166 a 5 divider and so forth. Now once you get up to 200Mhz and a 6
divider going to 233MHz and leaving the diveider at 6 would only put the
PCI bus at 38.8, which might be ok with some devices. So if there's no
manual setting for the devider in the bios, you have to hope that whoever
programed the bios had a little sense and automatically changed dividers
to the next level midpoint into the next 33MHz boundary. Some did, some
didn't. I've heard some didn't even program the top divider supported by
the chipset, but i don't know this for a fact. the one thing about a PCI
lock is that you don't have to worry about how the bios handles it. So for
people that don't know how all this works it's great, and not too bad for
the ones that do either.:-)

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
http://mysite.verizon.net/res0exft/cpu.htm
Anonymous
a b K Overclocking
November 21, 2004 5:43:24 PM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

"Wes Newell" <w.newell@TAKEOUTverizon.net> wrote in message
news:p an.2004.11.20.19.25.03.405982@TAKEOUTverizon.net...
> On Sat, 20 Nov 2004 17:41:36 +0000, jakesnake66 wrote:
>
> > My question is, with the various FSB speeds possible, is PCI lock always
> > advisable, and what about AGP lock? I used to have to worry about that,
but
> > I don't see much press on it right now.
> >
> The nominal pci bus speed is 33.33Mhz, and double that for thre nominal
> AGP bus speed. normally, the AGP bus is derived from just doubling the
> PCI bus speed so if It's locked Then they both should stay in spec. if one
> never changes the FSB speed, or keeps it on 33MHz boundaries then a pCI
> lock really serves no purpose. Go outside the 33MHz boudaries on the FSB
> and you may end up putting the PCI/AGP buses too far over spec for the
> PCI/AGP devices to operate properly. Before the PCI lock, the other buses
> were derived from dividers. For instance, with a FSB of 100MHz a divider
> of 3 was used for the PCI bus, and the pci bus was doubled. This sets the
> pci and agp buses in spec. Now if you raise the FSB to 133 and don't
> change the 3 divider, well, you end up with a PCI bus speed of 44.4MHz and
> an AGP bus speed of 88.8MHz. You'd be hard pressed to find any pci device
> that will run reliably over 40MHz. So at 133 Mhz a 4 diver is used, and at
> 166 a 5 divider and so forth. Now once you get up to 200Mhz and a 6
> divider going to 233MHz and leaving the diveider at 6 would only put the
> PCI bus at 38.8, which might be ok with some devices. So if there's no
> manual setting for the devider in the bios, you have to hope that whoever
> programed the bios had a little sense and automatically changed dividers
> to the next level midpoint into the next 33MHz boundary. Some did, some
> didn't. I've heard some didn't even program the top divider supported by
> the chipset, but i don't know this for a fact. the one thing about a PCI
> lock is that you don't have to worry about how the bios handles it. So for
> people that don't know how all this works it's great, and not too bad for
> the ones that do either.:-)
>
> --
> Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
> http://mysite.verizon.net/res0exft/cpu.htm

Thank you for the excellent explanation. I really appreciate it . . .
especially since you've probably explained it 100 here for guys like me :) 
The other question I meant to ask is, how do you know a board has PCI lock
prior to buying it? I think all of the recent Abit boards I've purchased
offered PCI lock, but I didn't know it beforehand. I don't recall ever
seeing it in product descriptions.

thanks,

jakesnake
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Anonymous
a b K Overclocking
November 21, 2004 11:20:56 PM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

On Sun, 21 Nov 2004 14:43:24 +0000, jakesnake66 wrote:

> Thank you for the excellent explanation. I really appreciate it . . .
> especially since you've probably explained it 100 here for guys like me :) 
> The other question I meant to ask is, how do you know a board has PCI lock
> prior to buying it? I think all of the recent Abit boards I've purchased
> offered PCI lock, but I didn't know it beforehand. I don't recall ever
> seeing it in product descriptions.
>
DL the board manual before purchasing. You should be able to find out
about all you want from that. Then also search for reviews on the board.

--
Abit KT7-Raid (KT133) Tbred B core CPU @2400MHz (24x100FSB)
http://mysite.verizon.net/res0exft/cpu.htm
Anonymous
a b K Overclocking
November 23, 2004 5:06:47 AM

Archived from groups: alt.comp.hardware.overclocking.amd (More info?)

jakesnake66 wrote:

>
>
> Thank you for the excellent explanation. I really appreciate it . . .
> especially since you've probably explained it 100 here for guys like me :) 
> The other question I meant to ask is, how do you know a board has PCI lock
> prior to buying it? I think all of the recent Abit boards I've purchased
> offered PCI lock, but I didn't know it beforehand. I don't recall ever
> seeing it in product descriptions.
>
> thanks,
>
> jakesnake


All mainboards with nForce2 has PCI Lock. KT880 has it too. that's the
only Socket A chipsets with PCI Lock. On AMD64 most new K8T800 PRO has
it and ALL nForce3 250.
!