Cyrix MediaGX
CyrixInstead
Posted 2017-07-03 3:35 PM (#784)
Subject: Cyrix MediaGX



Intel P5

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Location: UK
Hiya folks,

decided to pull out and set up the Compaq Presario 2232 machine I have owned for the last 4 years and setup some software on it. At the same time I got to think how little I know about this machine, not even sure of the clockspeed!
Speedsys refuses to run, just gives a black screen, CPU ID correctly identifies the chip as mediaGX but says 90 MHz, I'm sure that's wrong as the slowest I have seen mentioned is 133MHz.
Digging around in Google Groups, it seems the CPU is 200MHz in the 2232, can anyone confirm? So what FSB speed do these things run at? Or is that not really relevant considering the amount of stuff already on the CPU die?
Any info you folks might have on both the mediaGX and the presario 2232 itself I'd be interested to know.

All the best,
Chris





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Deksor
Posted 2017-08-25 12:28 PM (#887 - in reply to #784)
Subject: Re: Cyrix MediaGX


Chips 386

Posts: 34
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I've got the same laptop and indeed, mine has a 200MHz CPU. Apparently these Cyrix MediaGX are running with a 33MHz FSB rather than 66MHz like other socket 7 CPUs because inside the chip isn't a "586" but a 486

I've also read that this issue with speedsys happens on other Cyrix CPUs. However the program is apparently still running even though you can't see anything. At the end of the benchmark you can just save the results and this way you can see what results the CPU gave
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DXZeff
Posted 2017-08-25 1:00 PM (#889 - in reply to #784)
Subject: Re: Cyrix MediaGX



TM Crusoe

Posts: 618
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Location: Hull, UK
It seems the ALU and FPU are sat on an internal bus, so FSB is unknown as the clocks are likely internal. I think the chip needs an external clock generator or oscillator, but I'm not sure because of the diagram, those clocks in the datasheet I'm looking at might be coming out of the CPU and not going in.
If Deskor is correct, I've not seen anything to suggest otherwise as yet in regards to clock, and said clock is indeed set at 33MHz, that is interesting. The STPC runs at 66MHz and is definitely a 486 internally, I'd have expected the MediaGX to be faster despite being slightly older. That changes nothing here, but it's novel to think the low-power 486 possibly uses a faster bus than the MediaGX, I could have sworn the GX used a Cx586 core and that was a derivative of the 6x86 for 486 sockets... Bleh, strange chip.
Datasheet

With SpeedSys, check the "SPEEDSYS.TXT" file, I think you can make the program dump results to a PCX from the command line.

Not sure how I missed this thread.
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CyrixInstead
Posted 2017-08-26 5:15 PM (#894 - in reply to #887)
Subject: Re: Cyrix MediaGX



Intel P5

Posts: 85
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Location: UK
Deksor - 2017-08-25 12:28 PM

I've got the same laptop and indeed, mine has a 200MHz CPU. Apparently these Cyrix MediaGX are running with a 33MHz FSB rather than 66MHz like other socket 7 CPUs because inside the chip isn't a "586" but a 486

I've also read that this issue with speedsys happens on other Cyrix CPUs. However the program is apparently still running even though you can't see anything. At the end of the benchmark you can just save the results and this way you can see what results the CPU gave


Thanks, this thing is a slimline desktop machine however, not a laptop.
I'll have another go with speedsys when I have it set up again, mostly playing with old 8-bit machines in the small amount of time I have right now.

Best,
Chris
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Deksor
Posted 2017-08-29 10:08 PM (#896 - in reply to #894)
Subject: Re: Cyrix MediaGX


Chips 386

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Oh I see !

I'd love to have a desktop motherboard that would support the cyrix mediaGX CPU, they look so bizarre but so interesting at the same time ! It's a shame that mine is limited by the fact it's in a (crappy) laptop.
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DXZeff
Posted 2017-08-29 11:34 PM (#899 - in reply to #896)
Subject: Re: Cyrix MediaGX



TM Crusoe

Posts: 618
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Location: Hull, UK
Could be worth looking at industrial boards. They're not AT or ATX usually, but you may be able to find a PC/104 system or something which uses one, there were some other systems that used them which were desktop like, they're usually really expensive but you may be able to find one cheap if you save a search and check up on it every so often. It would help if you could discover some model numbers and whatnot, people sometimes list things by that for cheap if they don't know what it is.
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CyrixInstead
Posted 2017-08-30 6:47 PM (#901 - in reply to #899)
Subject: Re: Cyrix MediaGX



Intel P5

Posts: 85
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Location: UK
DXZeff - 2017-08-29 11:34 PM

Could be worth looking at industrial boards. They're not AT or ATX usually, but you may be able to find a PC/104 system or something which uses one, there were some other systems that used them which were desktop like, they're usually really expensive but you may be able to find one cheap if you save a search and check up on it every so often. It would help if you could discover some model numbers and whatnot, people sometimes list things by that for cheap if they don't know what it is.


Well I gave £4 for this Compaq 2232 Media GX a few years back at a boot sale, at the time i had no idea what it was, just thought the case was pretty cool, it was all complete apart from a hard drive.
Pretty sure this one has no MMX either so that Data sheet from DXZeff is for a later version of the CPU. One thing I can say for it, the internal speakers in the case are brilliant! It's got this tube that works as a trumpet/resonator, pretty cool, also let's you set the soundblaster parameters in the BIOS for dos stuff. I will say thought that in Win 95, the OS it apparently shipped with it's bloody sluggish, even with 40 MB RAM it is definitely slower that my cx 5x86 100 with only 32 MB.
It is an interesting machine, but i'd rather have had a good cx5x86 or even a DX/4 100 at the time for regular use, and considering this thing is from 1997, well a average socket 7 machine would blow it out of the water. It's to my mind a little like the VIA C3's, good enough if it's what you've got.
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Deksor
Posted 2017-08-30 7:13 PM (#903 - in reply to #901)
Subject: Re: Cyrix MediaGX


Chips 386

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If the CPU runs at 90MHz, then it's obvious it won't be better than a 486 clocked to a higher speed. However if it ran at 200MHz, it would be much better. My Cyrix mediaGX laptop can run carmageddon pretty smoothly for what it is. Obviously a slower Pentium will be better, but that's still something for something based on the 486 architecture !
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CyrixInstead
Posted 2017-08-30 7:48 PM (#905 - in reply to #903)
Subject: Re: Cyrix MediaGX



Intel P5

Posts: 85
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Location: UK
Deksor - 2017-08-30 7:13 PM

If the CPU runs at 90MHz, then it's obvious it won't be better than a 486 clocked to a higher speed. However if it ran at 200MHz, it would be much better. My Cyrix mediaGX laptop can run carmageddon pretty smoothly for what it is. Obviously a slower Pentium will be better, but that's still something for something based on the 486 architecture !


Well it can't be 90MHz, the slowest Media GX was 133 as far as I can find. Compaq used from 166 up as far as I can tell, so the upward model number suggests either 280 or 200 MHz in the CPU of my machine.
i really need to strip it and check, it's just not a very friendly machine to take apart!
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Deksor
Posted 2017-08-30 7:55 PM (#906 - in reply to #905)
Subject: Re: Cyrix MediaGX


Chips 386

Posts: 34
25
Maybe some jumpers are set incorrectly or something is missing, making the CPU running at an incorrect speed ? If you manage to make speedsys to work, it may help somehow to know what is actually the speed of the CPU.

You might also be interested to install the windows 98 version of CPU-z (yeah, CPU-Z is coming back to windows 98 for some reason)
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