HELP - can't get lower CPU multipliers to work on Asus A7N8X nForce2 mobo

[StevenG]

I'm really baffled by this, need some expert help. Just assembled an Athlon XP 2400+ on an Asus A7N8X motherboard. In stock configuration, the 2400+ uses a 133/266 FSB, a multiplier of 15, and runs at 2.0 GHz.

stock: 133 * 15 = 2000

I want to run the CPU at stock frequency (2 GHz), but with a 166/333 fsb. To do that, I would have to change the multiplier to 12.

desired: 166 * 12 = 2000

So, my plan was to first change the multiplier to 12, boot, and confirm with wcpuid that the computer is indeed running at 12*133 = 1600 MHz. Then I would go into the BIOS and increase the FSB to 166/333 to finish the job.

But I never got past the first step. When I changed the multiplier setting from Auto to Manual, then reduced the multiplier to 12, the PC refused to boot. The POST screen terminated with "WARNING - CPU has over speed" (sic) and would not go any further. The only way to proceed is to go into BIOS setup, and the only way to get the PC to boot is to set the multiplier to Auto.

This makes no sense - when I changed the multiplier to 12, I was UNDERclocking the CPU from 2000 to 1600. Why does the BIOS think I am overclocking? Any ideas what is going on here?

 

[ChampionAtTufshop]

i thought all kt400 boards unlocked all mults by default
maybe you still have to enable the lower multipliers on your cpu to have access to them

when you lower the mult to 12 iwhtout unlocking them, maybe the mult actually goes up some mults....

either way just try enabling the lower mults and give it a shot

 

[Ren2610]

It seems like you can only use multipliers above 15x in your case.

Looks like the multiplier can be adjusted upwards. There might be a possibility to enable the lower multipliers so that higher FSBs can be achieved. As this processor belongs to a friend, I don't think it's advisable to connect up the 5th bridge on L3 to enable the lower multipliers.

http://www.ocworkbench.com/2002/asus/a7n8x/a7n8xgallery3.htm



The A7N8X bios in itself appears to be buggy. I have a locked palo 1800+, but all the multipliers are selectable for it in bios ( according to the manual, that option should be greyed out ). If I choose anything below 11.5x, it will not boot. Any above 11.5 has no effect.

 

[caboob]

like the first nforce board, the high and low multis are shared in the bios. By default all the high multis are available so you have to connect that L3 bridge to enable the lower multis (which in turn disables the high multis). The KT400 (A7V8X) boards however give you full control of the multis.

 

[SFang]

do a search to find out a way to unlock your 2400+.

 

[chocoruacal]

I had a Gigabyte Kt400 board that couldn't use the lower multipliers, so not ALL Kt400 boards can.