Forced to underclock for stability :(

[atpat]

Abit NF7 v1, Athlon XP 3200+, Kingston ValueRAM 1GB DDR400 operating in Dual Channel mode.

I'm not trying to overclock this rig, just to get it to work at the specified speed. The NF7 is supposed to support this processor at 2.2GHz and a 200Mhz (ie. 400MHz) FSB with synchronous RAM, but after several days of experimenting I just can't get it stable at anything like that speed.

I have had this board for about 3 years, but stored it after failing to build a stable machine with it back then; but then I didn't understand about FSBs and multipliers and things, so I just gave it up as a bad job and bought a boring-but-stable Jetway board instead.

I've tried all sorts of combinations in the BIOS, all with a synchronous FSB/DRAM ratio (sometimes 3:3, but strangely 5:5 seems slightly more stable, though I can't imagine why; 1:1 is not an option in the BIOS). I can't get anything stable with an FSB above 174MHz unless I use the multiplier to slow the processor right down, and I've had to up the voltage to the CPU, RAM and chipset to get this stable. The PSU is new and is a decent 400W. Here are some examples of stable configurations:

(CPU speed/Multipler/FSB)
1870/11/170
2200/22/100
1830/11.5/159
2090/19/110
1190/7/170
1232/7/176
1240/7/177
1260/7/180 (200x7 is unstable)
1914/11/174 (ish)
1903/11/173

Now, I've read that, because a fast CPU and slow FSB leaves the processor hanging around waiting for more data to process, it is best to have the fastest possible FSB relative to the processor, lowering the multiplier to achieve this if possible. However, the Barton 3200+ seems to be locked to 7 or 11, except then using very low FSB values. Certainly trying a multiplier of, say, 10 makes the BIOS complain loudly at reboot, so it looks like I'm stuck with 173 or 174x11 as the fastest I'm going to get.

I benchmarked the CPU at this speed and found it wasn't going any faster than an Athlon XP 2200+, which is rubbish and indeed just wrong for 173x11.

What might be causing this lack of stability?

Why is it all processing so slowly anyway, judging by the benchmark?

What can I do to test different elements of the system to identify if one is faulty?

Is it possible to unlock the CPU so I can try other multipliers?

Help!

- Tony.

 

[Harvey]

I believe the problem is, your board is version 1. Abit says:

The NF7, based on nForce2 chipset (MCP + SPP), supports the latest AMD Athlon XP, Barton? processors with 200/266/333 FSB (400 FSB support in version 2.0 only)...

You have a nice board for trading toward a new one, but that's what you'll need to get your CPU up to speed.

 

[atpat]

Where did you find that? At the AMD specification page for the NF7 it says it does support the 400MHz FSB; either that or the way it is written is highly misleading.

 

[atpat]

...but I am being ungracious. Thanks indeed for the information. It's much appreciated, even if it means I'll have to fork out more of the hard-earned on another board!

 

[bluestrobe]

This model of board is nice but they had the model numbers setup confusing. I have one myself and have been tricked when looking for BIOS updates and drivers.

 

[atpat]

Originally posted by: bluestrobe
This model of board is nice but they had the model numbers setup confusing. I have one myself and have been tricked when looking for BIOS updates and drivers.

Do you mean a version 1 or a version 2? If so, can you confirm what Harvey says, that only v2 supports 400MHz FSB?

 

[bluestrobe]

They both support 400mhz FSB. How far did you overclock this processor before. The instability could result from past damage.

 

[atpat]

Originally posted by: bluestrobe
They both support 400mhz FSB.

Aha! Harvey, where did you hear that the v1 does not?

Originally posted by: bluestrobe
How far did you overclock this processor before. The instability could result from past damage.

I have not overclocked it at all, but I did buy it second hand. The seller assured me that he had never overclocked it, and I note from my data that it will run at its design speed of 2.2GHz, but only when the FSB is very slow.

I have heard that the NF7 v2 is much better than the v1. Perhaps the v1 just gets flaky if you try to push it to the recommended limit of 400MHz?

 

[bluestrobe]

Remember, there is a difference between NF7 v2 and NF7 2.0. I remember this from when I bought the board.

 

[atpat]

I have it on good authority that the CPU has been faked. See the discussion at the AMD forum for details.

 

[bluestrobe]

Thank God for eBay hardware and mass sellers.