Motherboard only works with a certain CPU?

[Tim]

In my Abit NF7 motherboard system (2 hard drives, 512 MB PC3200, CD-RW / DVD, and Windows XP Home), I have an AMD Barton 2500+ unlocked processor. It has always worked good.

I'm assembling a new system, consisting of a new (tested, bought from eBay) Abit VA-10 motherboard, Duron 1100 CPU, 256 MB PC3200 memory stick, CD drive, and Windows 2000 Pro.

The new system didn't want to work. I went crazy trying things for a while, then decided to do a one by one parts swap to track down the problem.

And yes, I tested the CMOS battery. I replaced the battery testing 3.0 volts with a new one testing at 3.10 volts.

I put some parts in the VA-10 from the NF-7. Memory, hard drive, CPU, power supply. And left the CD drive disconnected. It booted and ran fine.

I began taking the NF7 parts out and putting the VA-10 parts back in, one thing at a time. It kept working.

The only problem seems to be the CPUs. The Duron and Barton BOTH work fine in my NF-7 system, but ONLY the Barton will work in the VA-10 system.

The Duron gives lots of problems in the VA-10. Freezes, blue screens, incomplete boot ups, etc. But it works fine in the NF-7.

WTF is this? If the Duron were bad it wouldn't work in the NF-7 system, right? Could it only be a tiny portion of the Duron that is screwed up and causing the problems?

This makes no sense to me.

[Tim]

Well, it seems that the 1.75 volt Duron 1100 Morgan core isn't supported on this VA-10 motherboard. And the BIOS doesn't let you adjust the Vcore. Other CPUs right around 1.75 volts are supported, but not this one.

My NF-7 V.2 worked fine with both the 1100 Duron and my 2500 Barton. It auto-adjusted. I didn't have to do anything.

I guess you can't just drop any old Socket 462 processor into just any old Socket 462 motherboard.

That's news to me. You'd think the motherboard chipset would have this information and automatically adjust the voltages once it detects what CPU is installed.

There will be much more research the next time I buy a motherboard and CPU seperately.

[Thrax]

The chipset doesn't store any information.

It's all in the BIOS, and the BIOS doesn't have the CPUID codes for an ancient CPU.

[Tim]

Chipset, BIOS, whatever. The part that stores all the information. I thought there would be backwards compatibility.

As in - I would not expect a 3 year old Socket A motherboard to support a Sempron without at least a BIOS update, but I thought that any motherboard modern enough to handle a 333 FSB would know about and work with any 200/266 processor that fits the socket.

Evidently I was wrong. :shakehead

[muddocktor]

Not necessarily all the time, Tim. I had an Abit mobo that was also like this, the VH6-T. It could run Tualatin and Coppermine based P3's and Celeron's, but it couldn't run the older Mendicino based Celerons even though they were socket 370 based procs. You gotta remember that the VA-10 is a value board and most probably will be used with a new proc as a mobo/cpu upgrade combo or the basis of a cheap new system.

[Straight_Man]

Not necessarily all the time, Tim. I had an Abit mobo that was also like this, the VH6-T. It could run Tualatin and Coppermine based P3's and Celeron's, but it couldn't run the older Mendicino based Celerons even though they were socket 370 based procs. You gotta remember that the VA-10 is a value board and most probably will be used with a new proc as a mobo/cpu upgrade combo or the basis of a cheap new system.

Muddocktor hit the nail on the head-- trick is to see what motherboard supports what before you buy it, by getting the manual from the archives on builder's site, then looking at BIOS flashing availability to extend support in some cases to more than what the manual allows for.

[Tim]

I just got a 1.6 Ghz Duron on eBay. That is listed at Abit as a supported processor for this motherboard.

It had better work.