So You have 4x40MHz. I think that it would be interesting to try 3x50MHz. CPU will be 10MHz slower but bus will be faster.

Hmm, I don't want to crush your enthusiasm, but the result seems equivalent to the reference AMD Am5x86-160.

analog_programmer wrote on 2024-10-13, 18:35:

Hmm, I don't want to crush your enthusiasm, but the result seems equivalent to the reference AMD Am5x86-160.

How many people have a stable 160Mhz AMD 5x86?

fsinan wrote on 2024-10-19, 05:32:

How many people have a stable 160Mhz AMD 5x86?

Plenty on this forum:
Re: 5x86 question

fsinan wrote on 2024-10-19, 05:32:

How many people have a stable 160Mhz AMD 5x86?

*raises hand*

Ironically I couldn't get a stable 150mhz. don't recommend 3x50

fsinan wrote on 2024-10-19, 05:32:

analog_programmer wrote on 2024-10-13, 18:35:

Hmm, I don't want to crush your enthusiasm, but the result seems equivalent to the reference AMD Am5x86-160.

How many people have a stable 160Mhz AMD 5x86?

Me too. Nevertheless it's fun to OC and play around with this stuff. 50 MHz bus speed is indeed a challenge, the ISA/VLB/PCI bus will also operate at this frequency, so all devices connected to the bus are challenged. Not to mention you'll need super fast cache SRAM it can cope with.

Vote for 4x 40.

PD2JK wrote on 2024-10-19, 12:40:

fsinan wrote on 2024-10-19, 05:32:

analog_programmer wrote on 2024-10-13, 18:35:

Hmm, I don't want to crush your enthusiasm, but the result seems equivalent to the reference AMD Am5x86-160.

How many people have a stable 160Mhz AMD 5x86?

Me too. Nevertheless it's fun to OC and play around with this stuff. 50 MHz bus speed is indeed a challenge, the ISA/VLB/PCI bus will also operate at this frequency, so all devices connected to the bus are challenged. Not to mention you'll need super fast cache SRAM it can cope with.

It's all good fun, 40x4 is the sweet spot with my AP43.

I keep my 486 @ 3x50MHz. Yes, i couldn't use the absolute tightest timings on cache and ram though. But in the end, i truly enjoy the Trio32 memory bandwidth that comes with 50MHz VLB. (I refuse to use PCI on a 486)

I will have to try my DX4-120 at 150, then I'll have a fast 486 that actually says 486 on it. Though there's some stealth DX5 DX4s around that will probably do better.

I have 3x50MHz but it is not completely tested. I just build this machine, run some tests from Phils Computer Lab package which worked fine and I left it because I am working far from home and don't have much free time. I have some suspicions that it may be unstable because I don't have correct VRM for my motherboard and I am using cheap step down converter from aliexpress. This is another project to do - create good VRM but I have so many opened projects that I don't know when I will finish it, maybe on retirement.

fsinan wrote on 2024-10-19, 05:32:

analog_programmer wrote on 2024-10-13, 18:35:

Hmm, I don't want to crush your enthusiasm, but the result seems equivalent to the reference AMD Am5x86-160.

How many people have a stable 160Mhz AMD 5x86?

I had back in 1999, but I'm not sure if my criteria back then for "stable" were as strict as they would be today 🤣

fsinan wrote on 2024-10-19, 05:32:

analog_programmer wrote on 2024-10-13, 18:35:

Hmm, I don't want to crush your enthusiasm, but the result seems equivalent to the reference AMD Am5x86-160.

How many people have a stable 160Mhz AMD 5x86?

It's the go-to overclock for this chip without raising the voltage. As other user mentioned, 3x50 is also a nice alternative to run a faster bus. And if you like to push it, some can do 60x3 (4v). It depends a lot on the motherboard and your video card.

Back to the Am5x86@160MHz, it's crazy fast for all things DOS. In some things faster than an early Pentium. Even Win9x runs decently (95 is better). It's only surpassed by a Cyrix 5x86 or a Pentium Overdrive. But those aren't exactly 486 chips.

I have a 160 (4x40) that was overclocked since the 90's on a PCI motherboard. It was common back then to do this because it gave you early Pentium speeds without the cost.