PCI bus speed

YoungBlood · 14 Sep 2007 at 11:43

As far as I know, when overclocking the PCI bus speed has to be locked at 33mhz to avoid data corruption on the hard drives and general system instablity.

In my Bios I can't see any lock (Asus A8N32-SLI) and as I am running overclocked @ 9x290FSB im wondering what this has done to my PCI speed. Is there a piece of software than can pull this speed of the motherboard just so that I can check it is staying @ 33mhz?.

BigglesPiP · 14 Sep 2007 at 13:55

It has an Asyncrous PCI bus.

And if you've hit 290FSB, it's unlocked.

helmutcheese · 14 Sep 2007 at 14:10

Lock your PCI-E bus to 100mhz and your older PCI bus will be 33mhz. (you can go as high as 110-115MHZ to help GPU overclocks without any issues.

If you download Clockgen and open it you can see the Bus speeds like PCI 33mhz etc.

YoungBlood · 14 Sep 2007 at 14:12

BigglesPiP said:
It has an Asyncrous PCI bus.

And if you've hit 290FSB, it's unlocked.

Could you explain what a Asynchronous PCI bus is, I have no idea.

It's currently at 290FSB and stable, the PCI-E bus is showing as 100 but I want to make sure the PCI bus or whatever the HD's are linked upto is @ 33mhz or whatever it should be at.
I just downloaded a 300mb game demo which is corrupted so it's not looking good. Surely there is some software that will pull the bus speeds of the MB's. I know Abit had a utility for it on disc but im unsure with Asus.

EDIT
Thanks helmutcheese checking that now
EDIT2
Yes it would appear to be locked at 33.33mhz. Going to try to push it a little more, see if I can get 2.7 out of this X2 4200 - Thanks guys

helmutcheese · 14 Sep 2007 at 14:25

Thats cool, I know its locked if you lock PCI-E bus, mines it little high than 33mhz as I have the PCI-E bus locked at 110mhz.

BTW modern parts can handle higher speeds, most SATA HDD's are on the newer Mobos with a PCI-E bus so its 100mhz same with the GPU.

YoungBlood · 14 Sep 2007 at 14:35

Well I tried to take the FSB to 300 but it wont have it, even at 295. Seems the best I can do is 9x290 for 2.6 which is still pretty decent.

2.6 must be the limit of the CPU. To get that stable I have had to up the Vcore to 1.5 and it's giving me temps of about 64C under full load.

Shame, would have liked 2.7 or even higher to try to feed my GTX a little faster. Unless there is something else I can put more volts into, to help get a stable 300FSB?

But if you guys say put the brakes on now, then so be it

helmutcheese · 14 Sep 2007 at 14:48

Lower your Multi (to prove its not CPU limiting) set a divider for Memory (again to prove its not Memory limiting), then raise the HT (FSB)to that limit you have reached but increase the Chipset(s) voltages (NB/SB whatever) and try again.

If you get that HT (FSB) stable then raise Multi and CPU volts and try again, if it is again stable try get Memory IN Sync 1:1 with CPU (same speed), you may need increase Memory voltage.

YoungBlood · 14 Sep 2007 at 15:08

Lowering the multi from 9x to 8.5 or 8x is causing windows to bluescreen during boot up, despite the CPU clock then being only 2.3
Set at 9x it is 2.6 and boots into windows just fine. Memory is on 133 and the HTT 3x.
Don't get why it wont boot up with a lower multi though :confused:

helmutcheese · 14 Sep 2007 at 15:49

Make sure you got the Latest (Stable)bios for your Mobo, may nopt be the actual latest one, read reports see feedback, my latest beta bios is a ballsup.

YoungBlood · 14 Sep 2007 at 19:21

Yeah it's an aging board so no recent Bios build but I have the most stable recent one. Im quite happy with 2.6 the difference is extremly noticable in gaming.
With the thermal limit of the CPU around 70c and with 2.6 nudging 65c I think I have hit my air cooling limit.
Thanks for the help helmutcheese.