Re: 486DX-50 MHz EISA system

Posted on 2019-11-25, 00:00

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by mpe

in Marvin \ System Specs

in Marvin \ System Specs

Thanks. I will definitely post some results once the system is tuned. For now I am investigating some low VGA scores. Surprisingly the Winner 1000 cards returns identical or even little lower scores in EISA slot as opposed to ISA (and unsurprisingly well below an average VL-Bus card). I'd expect it …

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Re: AT motherboard and -5 volt rail

Posted on 2019-11-24, 23:56

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by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd say no. It is exposed on ISA slot. So depends on cards you are going to use. Most cards don't need it. But I have one which does need it - Sound Blaster 2.0 for amp. Newer cards don't need it.

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Re: Evolution of a Socket3 System to a POD @100MHz

Posted on 2019-11-24, 12:00

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by mpe

in Marvin \ System Specs

in Marvin \ System Specs

I know certain ALI chipsets from Pentium era used internal tag space which was sometimes combined with an external tag chip. It was a bit more complicated as there is no dirty tag per se in Pentium (instead there are MESI bits). In different revisions of the chip it was more or less broken which …

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Re: Desoldering/soldering Dallas RTC chip

Posted on 2019-11-23, 13:16

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Happy to report that I successfully soldered a DIP socket, installed a new Dallas and the board seems to be surviving my abuse. :blush: I only had very little previous soldering skills, just got TS100 soldering iron, sucker + other bits from eBay and watched a couple of YT videos about soldering 101 …

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Re: What are builds you want to make someday?

Posted on 2019-11-23, 00:28

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by mpe

in Marvin \ System Specs

in Marvin \ System Specs

486 build with Socket 6 That would be somewhat rare.

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Re: Post your 'current' PC

Posted on 2019-11-23, 00:09

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by mpe

in Marvin \ System Specs

in Marvin \ System Specs

I am using the entry-level 2017 iMac Pro with 8-core Xeon W CPU. It is a great system as far as general performance is concerned, but boots slower than the oldest system in my collection (1984 Macintosh 128k). A while back I recorded a short video about this: https://www.youtube.com/watch?v= …

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486DX-50 MHz EISA system

Posted on 2019-11-22, 23:59

by

by mpe

in Marvin \ System Specs

in Marvin \ System Specs

I like odd systems. You can tell as my other PC builds are Socket 4 P66 and NexGen Nx586. :blush:. However, I always wanted to build a `91 i486 DX-50 system. There is something fascinating about that once ultra-expensive CPU that was a king briefly and become unwanted when the local-bus came a few …

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Re: 486 cache trouble shooting ?

Posted on 2019-11-21, 21:17

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by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Do you have a better photo? I don't see any actual SRAM chips on your picture.

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Re: Very hot heatsinks of the voltage regulators on Socket 7 boards

Posted on 2019-11-21, 14:41

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd say this is normal. These parts often have operating junction temperature up to 150 or even 200 °C. Regulators get hot during operation. Just make sure they are separated from other parts which might not handle such a high temperature. On the other hand the dissipation is proportional to input/ …

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Re: How to go about putting thermal paste on ceramic Pentiums?

Posted on 2019-11-20, 23:47

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My Pentium board has a COAST module for L2 cache: https://en.wikipedia.org/wiki/Cache_on_a_stick So that's what some of those Socket 7 boards with the Slot-1 knockoff connectors use. :lol: I always was confused as to why it was there, because I knew they couldn't take Slot 1 CPU's, but this …

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Re: Fastest 486 CPU with 8k L1?

Posted on 2019-11-20, 12:49

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes. Definitely try it. OEM systems can be plagued by very weird compatibility issues and IBM are the worst. However, I'd be very surprised if L1 cache size was the problem. It's usually something else.

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Re: Fastest 486 CPU with 8k L1?

Posted on 2019-11-20, 10:19

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Is this your board? https://stason.org/TULARC/pc/motherboards/I/IBM-CORPORATION-486-PS-1-TYPE-2133-2155-2168-TYPE.html#ixzz2AtzV2UgX You should have a plenty of upgrade options: 1. 486DX2-66 (normal or overdrive any brand). 2. Intel DX4-100 overdrive (either ODPR or ODP). With properly set 5V -> 3. …

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Re: How to go about putting thermal paste on ceramic Pentiums?

Posted on 2019-11-19, 23:38

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by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

derSammler wrote: I'm a bit confused - ceramic Pentium MMX 200 MHz? 😲 I'm pretty sure that only the MMX with 166 MHz was ever available as ceramic. The 200 MHz one had a plastic package.y. Got one too. Too lazy to pickup my camera. http://cdn.cpu-world.com/Images/uploaded/0000 … /L_00000653.jpg

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Re: Fastest 486 CPU with 8k L1?

Posted on 2019-11-19, 18:13

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

No. They don't have regulators. Only the DX4 Overdrive (or Pentium Overdrive which goes to a different socket) does. And the DX4 Overdrive doesn't have the 169pin :) Other 486 overdrives are just re-packaged regular versions (OK sometimes with other minor insignificant changes to be absolutely …

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Re: Fastest 486 CPU with 8k L1?

Posted on 2019-11-19, 17:57

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

But you need the overdrive CPU with 169 pins. It has an extra pin in the center edge of the CPU. So look carefully for the Intel overdrive CPU with the extra pin. If that's the problem, then be assured that the extra pin doesn't have any electrical function. All it does is to prevent user from …

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Re: Fastest 486 CPU with 8k L1?

Posted on 2019-11-19, 17:12

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

This is not accurate. Intel DX4 with 16kB L1 CPU's can be either WB or WT (they have slightly different model number engraved on the top). These were available to OEMs only. I don't count them. When the retail DX4 arrived in October 1994, even the DX2 was switched to WB cache. I guess 25 years …

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Re: Fastest 486 CPU with 8k L1?

Posted on 2019-11-19, 16:54

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The problem is that all 486 CPUs with 16 kb L1 cache are using Write Back mode for it, unless you change it to WT in the BIOS (which you can't, since the BIOS does not know about it). . This is not accurate. Intel DX4 with 16kB L1 CPU's can be either WB or WT (they have slightly different model …

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Re: Fastest 486 CPU with 8k L1?

Posted on 2019-11-19, 15:57

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Don't have any experience with your PS/1. However, I'd be surprised if it's the cache that's the problem. It's usually something else (voltage, type of socket, bus speed...). Which PS/1 model do you have, what's it's current CPU and which DX4 did you try?

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Re: Evolution of a Socket3 System to a POD @100MHz

Posted on 2019-11-19, 14:49

by

by mpe

in Marvin \ System Specs

in Marvin \ System Specs

But there is no performance advantage against WT. On the contrary WT is often faster. I'd say it's complicated. Long books have been written about this (not just in CPU cache context, but in caching in general). I guess since your CPU's L1 is already WB mode, no matter how you se the L2 policy most …

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Re: Evolution of a Socket3 System to a POD @100MHz

Posted on 2019-11-19, 14:07

by

by mpe

in Marvin \ System Specs

in Marvin \ System Specs

It is not actually. As I understand the benefit of WB without tag is that the CPU doesn't have to synchronously wait for write operation as in write-through mode. Just when the cache line is about to be evicted there is a forced write (even if not needed). Depending on implementation and …

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