900 T-Bird, What Gives?

[dday]

OK, My question to you guys is about my T-Bird 900mhz.
Why won't this beast run at 133mhz and be stable ? I can get it to post and go into windows, but I get registry errors and a host of other funky things going on. I had it set to 8.5 x 133mhz(1130) and it chokes really big, set it to 8x133mhz(1064) and it will post, but falls all over itself. Currently ,and for quite sometime it has been running at 10x100(1gz) no problems at all.

System specs. Abit KT7A RAID , 256mb micron , 1.85v/core
and all the of the best bios settings I could get out of Pauls' Abit Pages. Any ideas would be appreciated.

[Thud]

If I remember correctly, some of the T-Birds were 100mhz (200 DDR) and some are 133mhz (266 DDR).

Could it be that your CPU's default FSB is only 100mhz, and the chip just won't overclock to 133? Also, if that's the case, it could be a PCI device that doesn't want to run that high.

That's what comes to mind first...sorry if I'm way off base!

[FreakyOCR]

A Tbird 900 is 100Mhz bus speed. Trying to get it to run at 133 means you are trying to make:

The processor, ram, PCI and AGP bus run at higher speeds.

If you have an option to make JUST the cpu run at 133 then it is simply becuase it cannot go that high.

It IS is 100Mhz (200 DDR) not a 133 (266 DDR) processor.

Hope this helps.

[otheos]

This is the KT7A board so running the CPU at 133Mhz won't run anything out of spec (KT133A).

However the CPU may or may not like the 133Mhz FSB, even at same clock speed as the original.

I mean that since the CPU is origianlly 9x100, it may or may not run stable even at 6.5x133= 866, eventhough this is less than the 900Mhz of the CPU. It's a matter of the CPU liking or not the FSB.

Give the 900Mhz parts were for some reason the less overclocking friendly, I would say that without considering the above, 1064Mhz may be 64Mhz too many.

You should follow the "standard procedure":

1. See how fast the CPU will go with only multiplier changes. This will show the MHz ceiling of the CPU.

2. Set the multiplier as low as possible and take the fsb at 133 and see if the CPU likes it.

3. combine the above for the best result (i.e stay below the ceiling with the max FSB possible).

All the best.

[Hellmund]

Maybe the cpu can't take 1.066ghz, try 7.5X133 for 1ghz, if it's still not stable and it is @10X100 then there is something else limiting your overclocking other than your cpu. The KT7A has the right AGP/PCI dividers for 133mhz

[dday]

Thanks for the info. people. I was begining to think it was me, as usual that was the basic cause. I have been known to really knock a machine dead with just a little effort ! It really seems curious that it will run @ 10x100 with no problems even doing burn-in tests and other bench-mark tests. But I haven't tried dropping the multiplier and using 133mhz yet, guess that's next.
Well it seems that there maybe a new 1.4 ghz waiting in the wings for me real soon! Thanks again for the ideas. I'll be playing around with it some more.

[Inferior]

Sounds like a bad batch for overclocking to me...

Some batch's of t-birds are amazing at overclocking (AXIA comes to mind here), others just dont cut it...

If the processor doesnt do that speed at 133, well it wouldnt do it at 100 either, the 100 (200 DDR) t-bird chips are quite good at doing 133 (266 DDR) at the same total clock speed...

And I didn't see you mentioning what type of heatsink you have, don't try overclocking that much if your not using an up to par heatsink....

[dday]

Well Inferior, I'm running a FOP38, and , yes it is pretty loud and it runs at about 6800rpm. The wife hates it! , getting fair temps and no locking up. But I bought it knowing that I was going to do this overclocking thing.
Otheos , I tried your method with settings and I came up with a stable run at 10.5x101fsb/33pci for 1061. It will post and run the CPU burn-in test in Sandra, but anything other than this setting using 133mhz above 6.5x133mhz and it chokes, won't post and ask for boot disk. or does goofy things if it gets into windows, I guess it just doesn't like the 133mhz settings.
Oh, Well ! It is now time to consider the best of the 1.3's - 1.5's for the next experiment!
I really appreciate the help ,you guys are great!