Are you sure it's not just the CPU? What happens if you drop the multiplier to 3x and try it at 120MHz (3x40MHz)?

I have three Am5x86 CPUs that happily do 3x50MHz but don't manage it at 160MHz, even if I raise voltage to 4V.

Am5x86 CPUs do regularly reach 160MHz and some even do 200MHz, but that doesn't guarantee they all do...

Here is a image from “Speedsys” program of what your benchmark score should look like for the GA5486AL over clocked with an AMD 5x86-133-P75 @ 160mhz.

most of my 5x86 amd. overclock to 160 always, but 1 chip does it 50% of the time. Once I was using that chip and I was sure the motherboard is faulty until I realised it works fine with other 5x86 chips at 160 just not one.

Also for more performance have you adjusted your memory timings in bios?

Memory timings is a good place to start. Not every stick can deal with 40 MHz at the fastest settings and even many cache chips can't take it. But with relaxed timings you should be safe.

Most VGAs I've ever tried could deal with 40MHz PCI. A Virge should be ok with it.

CPUs, on the othet hand... Of 20+ 5x86s there were a few that didn't even POST or boot DOS at 160 MHz stock voltage and only a few (I kept like 3 or 4) are stable in every motherboard, 3.3 or 3.45 Volts. Let alone my Shuttle HOT-433 with bulging caps which can overclock only ONE of those. Time to repair, I guess.

Does it work with L2 cache disabled and memory timings set slow? Single-banked cache implementations, such as that used on this board, will not handle fast timings at 40 MHz. Also, try a simple graphics card, like a Virge.

Some of the 5x86s don't overclock well. I have about five of these chips, and most do overclock pretty easily, but I have an ADZ which refuses to do 160MHz stably at any voltage, which is funny because ADZ was always regarded as superior to the ADW. I have 3 or 4 ADW chips and all overclock to 160, but my lone ADZ is a real turd.

Well i'll be damned!

Thanks for the help guys, great success!

I ended up just switching it to 40mhz with the 4x multiplier. Then disabled L2 cache, turned the memory timings to the slowest and then BEEP! it booted..... Happy times. I had done this prior, but never turned off the L2.

Then i turned on the L2..... BEEP! my jaw dropped.....

so, i thought let's just go all in.... Turned all my timings to 2-1-1-1 and set them to fastest.....
BEEP! what the hell???

Anyway, stock voltage 160Mhz and boots to windows without skipping a beat..... Here's my speedsys results.

This is why playing with old pc's is fun.... Because it seems you just need to choose the right day and hold your tongue the right way to get results!

I think I am using setting of:

Bios settings:
Clk/5
Timing = 3-1-1-1
WS=0