Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-24, 22:39
Today I found a Cyrix 5x86-100 Chip wit 4x multiplier in a scrap lot. It runs fine at 133 MHz 😀 Speedsys comparison with Am5x86-133 on HOT-433 Mobo:
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-27, 09:52
BastlerMike wrote: Today I found a Cyrix 5x86-100 Chip wit 4x multiplier in a scrap lot. It runs fine at 133 MHz 😀 Afaik not all Cyrix 5x86's even had the 4x multi, you should definitely keep it! 😉
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-28, 09:10
@Tertium Has your Cx5x86 133MHz arrived yet? Regards! (;
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-29, 11:31
udam_u wrote: @Tertium Has your Cx5x86 133MHz arrived yet? Regards! (; I haven't requested shipping yet (and not in a hurry either, sorry!). I'll report back when it arrives though, ok? All I remember is I'm getting a 3.6v variant (there were supposedly also 3.7v parts).
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-29, 12:22
I too have had few complaints w.r.t UMC's handling of PCI w/486 motherboards. For years I have been using a 3-slot PCI UMC-based 486 with PCI graphics, PCI SCSI, and PCI networking (Matrox G200, Adaptec 2940U2W, 3Com 3c905-TX-M 10/100Base-TX, respectively) in Windows NT 4.0 without incident. The …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-30, 15:03
@BastlerMike What RAM wait states were you using? What about cache timing? Did you determine if your 5x86-100/133 was stable in Windows 9X/NT or was it only tested with a DOS boot disk and Speedsys? A lot of times a system can appear stable in DOS but fail miserably with Windows. Your results seem …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-30, 15:16
@udam_u Did you ever retest for speedsys and cachechk results on your overclocked Cyrix 5x86 @ 150 Mhz? I was unsuccessful with this overclock operation, however I did not give it much time. I spent more time with the 66 Mhz FSB setting and getting it to run at 133 Mhz w/2x, unfortunately it will …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-31, 17:03
@Tetrium thanks - I will be waiting for info from you. I have to admit you are very patient. If I were you I would request shipping immediately. ^^ I wonder if this cpu is good overclocker - I would expect overclocking to150MHz without need to increase voltage above 4V. (; @feipoa Unfortunatelly I …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-03-31, 21:34
@Tetrium thanks - I will be waiting for info from you. I have to admit you are very patient. If I were you I would request shipping immediately. ^^ I wonder if this cpu is good overclocker - I would expect overclocking to150MHz without need to increase voltage above 4V. (; I doubt these CPU's are …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-01, 01:10
@udam_u I used an IBM 5x86-100HF with the factory blue anodized aluminum heatsink, but I modified it to accomodate a 1.5", 12V cpu cooler. The heatsink always feels cool to the touch. I think these IBM 100HF units are actually Cyrix 120 Mhz parts because, 1) On the ID1 register, it lists Stepping …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-01, 20:04
A v3.1 is preferred to a v3.0 as it has a socketed RTC. It was a scary exercise a few months ago to unsoldier all 24 RTC pins and soldier on a new Dallas RTC (ODIN is gone). If anyone has any spare 3.0 or 3.1's, please PM me. On page 1 of this thread, Vogons user Markk says that he has hacked an …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-02, 04:56
I do remember reading up on hack jobs for the RTC, but I do not think it is worth the risk -- other features of the RTC may be inoperative over time (i.e. square wave output, IRQ output, etc). It is a much safer route to replace the entire RTC with a new one. You can get a new Dallas RTC for about …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-02, 07:03
To shed some further light on the question I posed earlier about how to determine which PCI revision exists on your 486-era motherboard, the programs PCI104VK and PC-Config both say, "shows PCI-BIOS version 2.10" on my M919. This seems to be in agreement with Speedsys's claim for PCI 2.10 as well. …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-02, 09:26
@feipoa AFAIK steppings and revisions refer to improvements acquired during manufacturing process to fix functional bugs and sometimes improve manufacturing process. For me this mean only that your Cx5x86100MHz is newer than your IBM100MHz and cx5x86120MHz processor. However your observation can be …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-02, 10:46
@Tetrium We'd need to test both 3.6V and 3.7V varieties at various voltages to really determine what's up.[/b] This may be a problem, good luck finding both these chips :blah: Anyway, I might test it when I get it, but I'm in no hurry. I might test it along with a whole batch of other 486 CPU's I …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-03, 02:40
@udam_u Cyrix 5x86-100 Stepping 1 Revision 3 Fabbed 44th week of 1995 Cyrix 5x86-120 Stepping 0 Revision 5 Fabbed 50th week of 1995 It could be that the stepping/revisions numbers do not cross over between different speeds of the 5x86, that is to say that maybe stepping 0, rev5 of the 120 part …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-04, 21:36
Cyrix 5x86-100 Stepping 1 Revision 3 Fabbed 44th week of 1995 Cyrix 5x86-120 Stepping 0 Revision 5 Fabbed 50th week of 1995 It could be that the stepping/revisions numbers do not cross over between different speeds of the 5x86, that is to say that maybe stepping 0, rev5 of the 120 part contains …
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-04, 21:42
You guys need to get some "beastly" MediaGX hardware. It's the most refined Cx5x86 you can get. 😁
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-04, 22:36
I have a MediaGX motherboard and 2 CPU's but I can't get it to post, alas.
Re: UMC chipset PCI 486 mobo. AMD P90 CPU options?
Posted on 2011-04-05, 05:45
@udam_u The stepping/revision thing confused me as well. If I were to speculate, Cyrix probably realised that with branch prediction working, other enhancements did not (BWRT, LOOP, RSTK). An executive decision was probably made to not include this stepping rev. in the 120 Mhz cpus due to …
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