So it has ISA and VLB slots? Do you live in Texas or Louisiana? I'll make a day trip and come buy it from you hehe. If you have no use for it, you have an entire community here and eBay that would want something like that. It would actually round out my collection nicely.

johnnynismo wrote:

So it has ISA and VLB slots? Do you live in Texas or Louisiana? I'll make a day trip and come buy it from you hehe. If you have no use for it, you have an entire community here and eBay that would want something like that. It would actually round out my collection nicely.

Yeah it has, but I'm on another continent than you, unfortunately...
Besides - it having ISA and VLB is that special?

If I hadn't recently inherited a VLB system I would bite your arm off for it. They're curious boards as it's basically the fastest possible 486 system prior to PCI becoming the norm. Even then I think a well-tuned VLB system can be faster. So you're absolutely right not to get rid. Maybe someone who lives near you / in your country who is starting a collection would be interested?

brassicGamer wrote:

If I hadn't recently inherited a VLB system I would bite your arm off for it. They're curious boards as it's basically the fastest possible 486 system prior to PCI becoming the norm. Even then I think a well-tuned VLB system can be faster. So you're absolutely right not to get rid. Maybe someone who lives near you / in your country who is starting a collection would be interested?

but this one hasn't even 72 pin memory (EDO/FPM), memory throughput is really low on that thing. also the opti chipset doesn't seem to be the fastest one.
besides, that board was never meant to be with a "fast" cpu like the Am5x86-P75. Even during startup it says 66MHz, don't know if thats true, however as speedsys is showing P75-appropriate results.

Aren't there plenty of (better) vlb/isa boards out there?

nemail wrote:

but this one hasn't even 72 pin memory (EDO/FPM), memory throughput is really low on that thing. also the opti chipset doesn't s […]
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brassicGamer wrote:

If I hadn't recently inherited a VLB system I would bite your arm off for it. They're curious boards as it's basically the fastest possible 486 system prior to PCI becoming the norm. Even then I think a well-tuned VLB system can be faster. So you're absolutely right not to get rid. Maybe someone who lives near you / in your country who is starting a collection would be interested?

but this one hasn't even 72 pin memory (EDO/FPM), memory throughput is really low on that thing. also the opti chipset doesn't seem to be the fastest one.
besides, that board was never meant to be with a "fast" cpu like the Am5x86-P75. Even during startup it says 66MHz, don't know if thats true, however as speedsys is showing P75-appropriate results.

Aren't there plenty of (better) vlb/isa boards out there?

To be honest I have no hard figures to be able to say anything. Yet. I am in the process of creating three different 486 systems with different chipsets, RAM and buses to find out definitively which is quickest and then I'll know. I've heard SIS are strong performers, but I've also got a UMC and an ALi. All these mass benchmarks don't really carry a lot of weight in the absence of particular combinations of the theoretically best RAM, CPU and GPS combination. Ultimately I just want to know what the fastest convocation is of the hardware I've got, not what someone else has.

Thinking about it maybe you should keep it as a spare in case the other one dies.

nemail wrote:

..... Am5x86-P75.
Even during startup it says 66MHz, don't know if thats true, however as speedsys is showing P75-appropriate results.

There are two 2x multipliers in play in that setup.
The first is on the motherboard which is the 33MHz bus speed x2 giving you 66MHz to the CPU socket.
The second is inside the CPU giving you 66MHz x2 = 133MHz for the CPU's actual speed.
.
The P75 is a performance equivalent estimation/claim comparing it to a Pentium 75.
It's not the actual physical core speed of the Am5x86-P75 which is 133MHz.
They were aka Am5x86-133 or AMD X5-133.
.
They used to overclock those to 160MHz or 200MHz by setting the bus speed to 40MHz or 50MHz.
The problem is if you have VLB cards in use some don't like a 40MHz bus speed and almost none liked 50MHz.
.

All multiplication is done on the CPU. 33*4.

Multiplier was mapped 2 to 4?

gdjacobs wrote:

Multiplier was mapped 2 to 4?

Correct.

thanks for the clarification on the cpu frequency!
besides, i have decided to put the pc as-is to the basement, maybe i'll use or recycle it sometime...

feipoa wrote:

All multiplication is done on the CPU. 33*4.

Yeah, it's been something like 17 years since I played with one of those so my memory is a little off.
That's what I get for refreshing my memory at Wikipedia. (Which amazingly has been edited since I read it yesterday.)
I was trying to explain where the 66MHz reading came from and I missed by thinking the socket 2x jumper actually changed the system bus speed and not just the CPU.
Apparently his testing software detected the 2x jumper being in place and assumed that meant a 66MHz CPU.

Thing is you aren't 100% correct either.

The Am5x86-133 has both 3x and a 4x internal multipliers.
If you set the socket jumpers for 2x then the CLKMUL CPU pin is held low which gives you the 4x.
If the CLKMUL pin is held high or left open (left floating) then you get the 3x.
Please read page 14 (near bottom, left side) in the AMx586_tech-doc - attached.

The CLKMUL pin is R-17 on the CPU package.
The designation will vary on the socket side depending on which 486 socket you have. Best to look at the CPU then figure out which pin that is in your socket.

The implication of this is you can run an Am5x86-133 on an older board with no 2x CPU jumper you can still get 3x the bus speed for CPU frequency.
- Please note that sockets prior to socket 3 run a +5v Vcc and will require CPU voltage correction. The Am5x86 needs a Vcc of 3.45v +/- 0.15v.
.

nemail wrote:

Hi! […]
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Hi!

I've got this weird 5x86 system. It is based on some Opti-chipset motherboard which seems to support 386 and 486 and has VLB slots too as well as 256k cache. It has been upgraded to an Am5x86-P75 with a voltage regulator upgrade socket and has 20MB of 30 pin SIMM memory.
Besides that, it has a MiroCrystal 8S card (1MB, upgradeable to 2MB, S3 805 chip) and one 200MB as well as one 1GB hard drive, a cd drive and some old Sound Blaster card (CT2230) with Creative OPL installed.

I can really make no use of it because I have another Am5x86 system based on a PCI board with SCSI in place so I'm wondering what to do with that piece of history.
It is very nicely installed by the pre-owner, btw. When you start it up, tons of drivers load and a McAffee virus scan starts and Windows 3.1 is full of program groups so that is a "real life" machine which appareantly has been heavily used back in the days.

(The case is a very nice big tower too, btw)...

should I take it apart, should I keep it as it is, until I need one of the installed parts? should I sell it?
I honestly don't know... 🙁

edit: it is actually that system:
Again new 486 build (Am5x86)

nemail wrote:

thanks for the clarification on the cpu frequency!
besides, i have decided to put the pc as-is to the basement, maybe i'll use or recycle it sometime...

Recycle ? 😳
man, don't do this.

🤣 at that futurama Quote 😁

matze79 wrote:

Recycle ? 😳
man, don't do this.

whooops, i didn't mean to recycle in Terms of throwing it away but in Terms of reusing all of its parts in other Systems (maybe sometime)... 😀 no worries

nemail wrote:

🤣 at that futurama Quote 😁

matze79 wrote:

Recycle ? 😳
man, don't do this.

whooops, i didn't mean to recycle in Terms of throwing it away but in Terms of reusing all of its parts in other Systems (maybe sometime)... 😀 no worries

Matze is going to hunt you down and chain himself to your 486.

brassicGamer wrote:

nemail wrote:

🤣 at that futurama Quote 😁

matze79 wrote:

Recycle ? 😳
man, don't do this.

whooops, i didn't mean to recycle in Terms of throwing it away but in Terms of reusing all of its parts in other Systems (maybe sometime)... 😀 no worries

Matze is going to hunt you down and chain himself to your 486.

🤣 🤣 🤣 🤣 🤣

brassicGamer wrote:

Matze is going to hunt you down and chain himself to your 486.

Is okay.
I have bolt-cutters and cutting torches for such situations. 😊