View Full Version : Slot A upgrade problem - cast your mind back ;-)

15th September 2002, 09:01 PM
Okay, I have a crisis with a Slot A Athlon, which I have to admit I was never involved with (I was toying with O/C'ed Celerons in those days )

I'm trying to upgrade a computer for a friend, and I have a little known motherboard called the NMC-7VAX a KX133 motherboard currently running a 500 Athlon (or rather K7 because it's too early to be called an Athlon).

I bought a 1000mhz, well, 900mhz soldered overclock chip before I saw the MB. Now it turns out the motherboard only supports up to 850

Is this a voltage issue, or are the fundamental changes to the architecture just too different ? The machine posts and recognises the chip, but then locks up on the POST screen... If you can all drag your memories back that far, any suggestions would be incredibly welcome !!


15th September 2002, 09:08 PM
Unfortunately I can't help you much on this as back in those days I was an Intel man until the prices got too steep and AMD had some really good performance CPU's.

I am thinking it's a problem with the FSB or something? Maybe trying to go too high and the board just says :xwtf: ...

Mad Bad John
15th September 2002, 09:32 PM
Greetings Danb

as a slotter I may be of some assistance - the best guy to talk too on SlotA is Lolboy ( he visits the SlotA section on a regular basis - try posting there.)

Not having heard of your MB I can only make some general suggestions, the first is obviously try and update the bios, and then depending on how this K7 has been soldered try kicking up the core voltage ( if your cooling is good you should be able to run up to about 2.0v.

With ref to sevens fsb suggestion , make sure your not trying to oc on the FSB as well.

If your K7 has been soldered as you say then it should only have had the multipiers and maybe cache ratio changed, leaving you to set the core volts in the bios.

All the best MBJ

16th September 2002, 08:52 AM
What I'm worried about, having thought about it overnight, is the multiplier.

As I see it, all these Athlons ran on a 100mhz bus. Therefore the 500 had a 5 multiplier, the 600 a 6 etc.

I strongly suspect that the motherboard supports multipliers from 5 to 8.5, and no more. If that's the case, and the multiplier on this CPU is soldered at 10, then I think I'm screwed ?

16th September 2002, 09:14 AM
If that is the case (up to 8.5x supported) then your only option seems to be to modify the Athlon to have an 8.5x multiplier....

Could be wrong, ask Lolboy :D


16th September 2002, 01:24 PM
the problem is the processor itself rather than a multiplier.

athlon above 800 or so come with a thunderbird core, and its not compatable with alot of older slot a mobos's (the abit ka7 springs to mind)

its up to you weather you scratch around to find a 750 processor or replace the lot with a ddr board and a duron

toodles :xsofa:

16th September 2002, 06:21 PM
Hello People, you called?

There a few manufacturers that say their boards only support processors up to 850meg cos that was as fast as the chips went when the motherboard was produced and the documentation written.
As suggested before by MBJ, check for bios updates. If it wont run it then underclock (dont say that too loud!) it to a 8.5 mulitplier.
Also, you can get classic slot A Athys faster than 800meg (MrP your out of practice!) but he's right about some mobos not supporting T'bird Athys over a certain speed. What you got a classic or T'bird?


16th September 2002, 10:13 PM
Okay guys, things have moved on now, and I *really* need your expertise now !!

- Got a new bios
- Got a list of the jumpers (which control voltage)
- Got the latest via 4in1's
- Installed the above

The machine boots now, and goes into safe mode just fine. However, no matter what I try it always gives Windows Protection Errors when I try to boot normally. I don't understand. On default, the board put 1.9v to the chip. I've also tried 1.8 and 1.7 (and even 1.6 !) with no improvement. I've got two DIMMs but have tried with a single one. It doesn't even seem to be a heat problem - the CPU is reading 25 degrees centigrade. When in safe mode, I can run 100% loading CPU tests no problem.

Oh yes, and I've tried the FSB all the way back to 83, which brings the chip below it's original 900mhz rating ! (It's supposed to be soldered to do 1gig on a 10 multiplier).

Any suggestions again ? Thanks for all your help so far.


16th September 2002, 10:18 PM
Windows XP?

Reinstall Windows while using the settings you wish to use if that's the case. XP gets picky on things like that if you are using it.

16th September 2002, 10:21 PM
Nope - it's an older machine, so Win98SE. It's also a friend's machine, so I'm loathed to reinstall unless absolutely necessary (and I'm not sure he was even given the installation discs with the PC when he bought it 8-( )

Mad Bad John
16th September 2002, 10:36 PM
Remove all uneccessary cards - maybe try pci graphics card instead - run scandisk, try another psu , reseat all components ? spect you already tried some of these


16th September 2002, 11:03 PM
Hi Guys
Can you tweak the voltage a bit more, try 1.95 or 2.0v that may just do the trick :)

Jed ;)

17th September 2002, 08:39 AM
The only other component is a PCI modem, but I can try removing that. I have defragged. I think the max voltage is 1.9 - sure if I'm underclocking to 830 even that would be enough ?! I will try another PSU - that had crossed my mind but it's not easy to get my other one out 8-(

18th September 2002, 10:54 AM
i stil think its the thunderbird core causing the problem

as i remember, the abit KA7 wouldnt run a tbird core over 850.

this might be the same problem


18th September 2002, 11:03 AM
Even though it will run in safe mode ?