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AMD 5x86 X5-133 (now with POD)

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Reply 61 of 92, by derSammler

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Today, I finally replaced the AMD 5x86 X5-133 with an Intel Pentium Overdrive. And guess what? It blows the X5 away even at 83 MHz and the X5 running at 160 MHz. Speedsys gives 59 for the X5 at 160 MHz and 60 for the POD at 83 MHz. Quake timedemo results in ~16 fps for both, but the game still plays much better on the POD, since there are no slowdowns as with the X5. The X5 reaches higher fps on very simple scenes, but completely fails when light effects are kicking in.

IMG_20190702_192332065.jpg

Tried the POD at 100 MHz, which gives almost a score of 73 with speedsys. Sadly, it's not running stable at 100 MHz. But I'm very pleased with it even at 83 MHz. 😀

Reply 62 of 92, by Intel486dx33

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How well did it play MP3 files with Winamp program on the AMD-5x86-133 and on the Intel Pentium overdrive CPU ?

Last edited by Intel486dx33 on 2019-07-03, 17:09. Edited 1 time in total.

Reply 63 of 92, by derSammler

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With WinAmp 2.95, it plays MP3s just fine, and you can still click around in Windows without getting drop-outs. But even my DX4-100 with no L2 cache does not struggle with MP3s (well, using 8-bit playback there, as the used sound card is buggy in 16-bit). All my MP3s are 192 kbps, however, it may not work well with higher bitrates.

Reply 64 of 92, by Intel486dx33

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The purpose for building a 486 66/100mhz or AMD 5x86-133 is so you can downclock the CPU between 25mhz and 133mhz.
You can do this with the Turbo switch cutting the CPU speed in half to 66mhz from 133mhz. and then with the "Setmul" utility reducing the CPU down to the performance of a 386sx-25mhz.
By disabling the CPU L1 cache. Reason to do this is to be able to play CPU speed critical old DOS games like "Wing Commander-1"
This way you can play a large range of DOS games on your computer. Old and Modern DOS games.
By putting an Intel Pentium over drive CPU in your computer you may be unable to get to these Low CPU speeds.
Check and see how low you can clock down your computer with the Turbo switch enabled and L1 Cache disabled.
You can disable L1 CPU cache with "Setmul" utlility.
You can use a benchmark utility like "Topbench" to check your CPU speed in real time. And "Speedsys"
Otherwise you just have a regular class Pentium computer. I thought the purpose for these old DOS computers was to play as many old DOS games.

Reply 66 of 92, by bjwil1991

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Doesn't the Pentium OverDrive, much like the early Pentiums of the early 1990's have the infamous FDIV bug? I had a POD-83 until the pins got bent accidentally and it won't run without them. I have an Evergreen 586 (DX5-133) in my Packard Bell Pack-Mate 28 Plus and it runs better than the DX4-100 OverDrive. Might get another Pentium OverDrive sometime, but, they charge a lot for a used one that's not in a box.

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Reply 67 of 92, by derSammler

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@Intel486dx33:

I'm not really interested in having one retro system for all games. I have other systems ranging from an original 5150 up to a 486dx2-50 for older games - and also faster systems for newer games. In most cases though, I just use MoSlo, which works for most old games on faster systems just fine.

However, the POD has a nice feature if you care about slowing down: removing the fan (or cutting the sense pin) sets the multiplier to 1x, so you can run it with 25 Mhz if you want. With no L1/L2 cache, it will probably crawl like a fast 286 then.

Doesn't the Pentium OverDrive, much like the early Pentiums of the early 1990's have the infamous FDIV bug?

Most likely, yes. But the bug isn't really relevant unless you use the system for scientific work. And even then, you probably won't ever notice it. (edit: according to most sources, the POD is not affected by the FDIV bug)

Reply 68 of 92, by theplum

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derSammler wrote on 2019-07-02, 18:32:

Today, I finally replaced the AMD 5x86 X5-133 with an Intel Pentium Overdrive. And guess what? It blows the X5 away even at 83 MHz and the X5 running at 160 MHz. Speedsys gives 59 for the X5 at 160 MHz and 60 for the POD at 83 MHz. Quake timedemo results in ~16 fps for both, but the game still plays much better on the POD, since there are no slowdowns as with the X5. The X5 reaches higher fps on very simple scenes, but completely fails when light effects are kicking in.

IMG_20190702_192332065.jpg

Tried the POD at 100 MHz, which gives almost a score of 73 with speedsys. Sadly, it's not running stable at 100 MHz. But I'm very pleased with it even at 83 MHz. 😀

I have a similar setup (M919 with 256k cache) but after upgrading my x5-133 to ODP 83MHz my network card does not work and the 256k cache cannot be detected by cachechk. Any special setting for this? 😒

Reply 69 of 92, by derSammler

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Since these things are not really related, I would guess the PSU has weak caps and can not provide stable 5V when the POD is installed, making some components fail or not working correctly. Try a different PSU.

Reply 70 of 92, by theplum

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derSammler wrote on 2020-01-04, 15:33:

Since these things are not really related, I would guess the PSU has weak caps and can not provide stable 5V when the POD is installed, making some components fail or not working correctly. Try a different PSU.

O... in fact I am using a modern PSU (with ATX to AT adapter) which focuses on 12 v. So any solution to this? 😞

Reply 72 of 92, by theplum

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derSammler wrote on 2020-01-04, 16:04:

Well, you would need to test it with a different PSU first. It may not even be the culprit, but you won't know before testing. Don't you have another PSU?

Well...I have other PSUs but they are in use so I can only try them out tomorrow...

Reply 73 of 92, by theplum

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derSammler wrote on 2020-01-04, 16:04:

Well, you would need to test it with a different PSU first. It may not even be the culprit, but you won't know before testing. Don't you have another PSU?

By the way, I have discovered that this item on my board is missing (indicated by the red circle). Can this be one of the reasons?

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Reply 74 of 92, by derSammler

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That black MOSFET? That shouldn't be missing, as it provides power for the CPU. Can you please share a picture of your board with a close-up of that section? Makes me wonder if it was once there or already omitted by the factory.

Reply 75 of 92, by theplum

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derSammler wrote on 2020-01-05, 09:18:

That black MOSFET? That shouldn't be missing, as it provides power for the CPU. Can you please share a picture of your board with a close-up of that section? Makes me wonder if it was once there or already omitted by the factory.

I have noticed that my M919 board version is v3.2. I tried to search for the web and found that all v3.2 M919 boards have only one MOSFET...

Also, I tried another PCI NIC and it doesn't work either. An ISA NIC works fine, though...

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Reply 76 of 92, by CoffeeOne

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I guess the missing MOSFET is no problem anyway, because you have a 5 volts CPU, so the voltage comes directly from the power supply.

Having faults with PCI cards (but working with ISA cards) is a bad sign, your system is not trustworthy.
CPU is normally not a problem, but be sure that you use 33MHz (do not overclock to 40!).
So then ....
Try disabling the L2 cache (or removing the module) AND the slowest RAM settings. Yes, no kidding I mean really the slowest setting (most wait states).
Then try again with the PCI network card. If it works, then put again the cache module in, but keep memory setting at slowest and test again.

Reply 78 of 92, by theplum

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CoffeeOne wrote on 2020-01-05, 13:48:
I guess the missing MOSFET is no problem anyway, because you have a 5 volts CPU, so the voltage comes directly from the power su […]
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I guess the missing MOSFET is no problem anyway, because you have a 5 volts CPU, so the voltage comes directly from the power supply.

Having faults with PCI cards (but working with ISA cards) is a bad sign, your system is not trustworthy.
CPU is normally not a problem, but be sure that you use 33MHz (do not overclock to 40!).
So then ....
Try disabling the L2 cache (or removing the module) AND the slowest RAM settings. Yes, no kidding I mean really the slowest setting (most wait states).
Then try again with the PCI network card. If it works, then put again the cache module in, but keep memory setting at slowest and test again.

Hmm... I have checked the spec of my PSU... the highest current for 5V is 15A, is that enough?

I am not good at overclocking so I keep everything default (2.5 x 33MHz)
When I use AMD X5-133 everything (L2 Cache, PCI NIC) is fine.
Ah I forget to mention...... the L2 cache is not displayed when using cachechk when POD is used, but it can be detected by speedsys