sis755 for athlon64. which fsb tool?

[s e t h]

i have a jetway s755max motherboard in for testing. unfortunately the bios' max fsb setting is 232. not nearly enough to test the fsb potential of the sis755 chipset. it benches stable at 232fsb easily.

does anyone know which program might be able to raise the fsb from within windows? clockgen works fine to lower the multi and the lower multi holds during restarts.

some features of the board include vcore up to 1.7 and vdimm up to 2.8. also not enough for semi serious clocking. mods should be available in a short while though.

there is an isl6559cb chip near the cpu and mem but this is probably the vcore regulator.
also a realtek chip near the agp slot numbered rtm360-755r may have something to do with the fsb.

any help pushing this board appreciated.

[Penti]

The rtm360-755r ic-chip is the clock generator. But it almost seems limited to 232MHz sinced all other SIS755 boards i've seen have hade its limit at 232MHz. But that could probably be becuse they follow SIS reference design maybe, but also becuse of the clockgenerator.

There are no datasheet for the clockgenerator availble for the public anyway. But they are clockgen etc for other realtek pll's might worth a try.

Otherwise Turbo PLL

[s e t h]

i tried one of the realtek one for rtm360802 from clockgen - no worky.

i will try turbo pll thanks Penti. you got a link? google is a bit sparse

[Penti]

Hehe.
I meant Turbo PLL as exchanging the reference crystal to an adjustable, running the clock, usb, floppy. 14.318, 48, 24MHz on there own signals. There for can run higher fsb due to higher reference clock.


Borrowing picture from Macci

[s e t h]

hmmm. maybe i wait for clockgen. i emailed them and realtek already

[freeloader]

Do you know if there happens to be a PCI/AGP lock on your board?

[Warden]

The preview I read of the SIS Chipset stated that it had both PCI and AGP Lock

Warden

[s e t h]

i benched it at max fsb and got no corruption on my raptor. a good sign cause the raptor has corrupted at 222fsb on all athlon64 boards i've driven so far.

[Soulburner]

Originally posted by flytek
hmmm. maybe i wait for clockgen.

It doesn't matter if you use the BIOS or Clockgen, if the clock generator can't do more than 232mhz you will be limited to that no matter what, unless you rig up a Turbo PLL...

[s e t h]

maybe i should mail for a decent bios. i hope the realtek clockgen isn't the limit. this puppy feels like it wants to do much more

[Penti]

The ECS SIS755 board also has it limit at 232MHz fsb, run fine there too from what i've heard. However Jetway and ECS doesn't use the same Clock Generator. So the 232MHz limit can be BIOS related. I to would like to see what an SIS755 board could do, but i guess there are not enough data out to make an pll-file for software like setfsb, softfsb, clockgen. Hope there come up something this chipset could do much more.

[mearle73]

There is no agp/pci lock on the jetway 755max,I put it on the pc giger the agp/pci rise with the fsb.

[s e t h]

so how come my raptor never corrupted on this board when it has corrupted on all others? maybe the s-ata cotrollers are not as sensitive to high fsb or something?

[halcyon]

mearle73,

How do you know that Jetway 755max does not have agp/pci lock?

[Penti]

halcyon

Like he said he tested with a pc geiger.

[mearle73]

I also asked jetway here is there reply


"Dear sir

I am sorry , the apg/pci clock will not fixed in 66/33MHz when you over clock .

Best regards
From JETWAY FAE support team"

[Soulburner]

So then either the fixed AGP/PCI for SiS755 is a lie, or Jetway didn't even implement the feature. But how do you mess that up?

[Speed_Mechanic]

Asus didn't implement a locked PCI in their NF3 board either, but it seems fine for most other NF3 boards.

[Penti]

Originally posted by Soulburner
So then either the fixed AGP/PCI for SiS755 is a lie, or Jetway didn't even implement the feature. But how do you mess that up?

Probably by using a clockgenerator without support for fixed/asyncronomous PCI/AGP. Manufactures of budget boards would hardly care about it since the board aren't meant to be a overclocking boards anyway.

Speed_Mechanic
I've havn't yet seen a board that for certan got fixed PCI freq. The Shuttle has divider too not just the asus, since so many boards don't got fixed/async PCI it seems more like chipset related.

[freeloader]

Penti...to which Asus board are you referring and what divider? As far as I know the K8V only has a 1/6 divider. That's it.

[Penti]

freeloader

I was talking about nForce3 150 not via k8t800 and i wasn't saying that it got fixed/async PCI.