VOGONS


My Big Red Switch 486

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First post, by firage

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SYSTEM COMPONENTS

ASUS VL/I-486SVGOX4 Rev. 1.5 (BIOS 0402.001)
Write-Back Enhanced Intel DX4 100MHz (SK096)
32MB 60ns 72-pin FPM SIMM w/ Parity (HYB5117400BJ-50)
Hercules Dynamite Power VLB (ET4000/W32p)
Creative Sound Blaster Pro 2 (CT1600 Rev. 07)
Gravis UltraSound MAX 2.1
Roland SCC-1
Roland MT-32 ("Old" PCB Rev. 01)
Promise EIDE2300Plus
Teac CD-55A SuperQuad
Y-E Data YD-380B-1736B00W 5.25"
Panasonic JU-257A606P 3.5"

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ASUS VL/I-486SVGOX4 Rev. 1.5:
Very similar to VL/I-486SV2GX4 Rev. 2.0, just with the addition of 30-pin SIMM slots. I've used the same updated BIOS on both board models. Thanks to keropi for hooking me up with the ROM many years ago.
I've got 1024KB of 15ns ISSI (probably re-marked) SRAM installed. The RAM stick is a pretty nice 72-pin 60ns FPM SIMM with 50ns rated chips, 32MB dual sided.

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Hercules Dynamite Power:
The ET4000/W32p based video card is great and it was a standard for the demo scene. A pair of games with severe compatibility issues were Apogee's Crystal Caves and Secret Agent, until K1n9_Duk3's recently developed fixes.
My Cirrus Logic GD5429 has the same fast 45ns memory chips on it. Didn't get far with a comparison, as it's not recognizing half of the memory and bandwidth is halved.

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Sound Blaster Pro 2:
This one's a late revision of the CT1600 and sounds pretty good to me. SB Pro's have tons more 'character' than newer cards and in many cases the sound is just right. The heavy lowpass filtering on the output can be enabled or disabled in software. I have the card set at the original SB defaults of I/O port 220, IRQ7, DMA1.

Gravis UltraSound MAX 2.1:
Learned that the CD-ROM enable jumper does need to be set to enabled also for the Panasonic interface. Everything I've found online regarding the 2.1 MAX revision says the opposite. I have the GUS at I/O port 240, IRQ11, DMA5, MIDI IRQ 5, which seems to work best for most games.

Roland SCC-1:
Equivalent to SC-55 version 1.2x plus an intelligent mode MPU. Features Capital Tone Fallback and drum channel program changes also fall back to nearest like early SC-55's. GM standard configuration of PC#122 Breath Noise / Fl. Key Click, but doesn't have the additional instruments from SC-55mkII.

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Promise EIDE2300Plus:
I had high hopes for the EIDE4030Plus caching controller instead, but just couldn't get the performance out of it.
The EIDE2300Plus supports transfer modes up to PIO Mode 3 (~180ns cycle time) or MWDMA 2 (~120ns cycle time). No bus master DMA. Bases PIO cycle times on system bus clock, i.e. PIO 3 should run at PIO 4 on a 50MHz bus. Requires a 7kB driver to enable transfer speeds above those of ISA based controllers.
If the adapter ROM is enabled, the controller will reduce the first 640kB of conventional memory by another 3kB, besides its UMB footprint; I have no need for it, because the motherboard BIOS already supports LBA without an extension and there's no other benefit in any measurements.
I've got a 2GB Transcend CF100i CompactFlash for a hard disk for now; DMA benchmarks are good but not spectacular. Something else might be able to deliver the ultimate performance here.
Update: Updated after successfully enabling MWDMA and reran benchmarks.

Teac CD-55A SuperQuad:
4X (~590kB/sec) transfers on the proprietary Panasonic CD interface. The polling interface doesn't use up IRQ/DMA resources, but it'll load the CPU hard in a multi-tasking OS. Its seek times are a little on the high side for a quad speed and the buffer is meager at 64kB, more befitting a double-speed. Sounds nice and quiet, reads CD-R's.
Regarding period correct CD-ROM drives in general, it's worth noting that their audio output quality varied back then; a handful of drives came out with 100dB SNR analog circuitry, but most were less than 90dB and there was a trash tier of drives at/under 80dB SNR. I don't know exactly where the Teac sits, but newer drives do sound clearer. With this particular build, I don't mind a bit of color in the sound.

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The case and the 200W Tiger Power (Lead Year) Super 2200 power supply:
The base for this late 486 build is my very first PC from 1992. It was originally an Am386DX-40 with some rough styling already going out of fashion. The PC building outfit's work wasn't clean either, grody steel surfaces and markered up screws. Very industrial. Nice heavy "clunk" action on the big red power switch.
It's pretty cramped with all the stuff I have in there. I haven't finished tidying up the cabling mess yet.
The power supply is not well known, but seems good. I put in a new fan a few years back.

BENCHMARKING

Doom [full graphics, no sound]: 41.6 fps (1795 realtics)
Superscape 3D Bench 1.0c: 68.5 fps
PC Player Bench [320x200]: 22.3
Quake: 11.0 fps (88.3 sec)

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Scaling with turbo:
Doom: 15.9 fps (4688 realtics)
Superscape 3D Bench 1.0c: 31.2 fps
PC Player Bench: 9.5
Quake: 5.2 fps (186.8 sec)
Ultima VII guard roundtrips only take ~28.5 seconds. The game still runs too fast, 1.66x the rate of the theoretical 486DX33 and 1.33x the hard speed cap set in Serpent Isle.

Scaling with turbo, detuned BIOS settings, L2 cache disabled:
Doom: 11.4 fps (6553 realtics)
Superscape 3D Bench 1.0c: 18.5 fps
PC Player Bench: 4.8
Quake: 3.3 fps (289.6 sec)
Ultima VII guard roundtrips clock at ~42.0 seconds, which is a very good rate for the game.

Scaling with L1 + L2 caches disabled:
Doom: 4.0 fps (18 810 realtics)
Superscape 3D Bench 1.0c: 10.4 fps
PC Player Bench: 2.8
Quake: 2.0 fps (491.5 sec)

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Last edited by firage on 2020-04-04, 11:13. Edited 8 times in total.

My Big Red Switch 486

Reply 4 of 37, by firage

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No, GUS doesn't do intelligent mode. I'm using the SCC-1's MPU interface for MIDI. The MIDI Adaptor is mainly useful for splitting the GUS gameport for two controllers here.

Intel486dx33 wrote on 2020-03-13, 12:10:

Very nice. That’s more of a 1994 build. I can down clock my 486dx4-100 to a 286@10mhz using the turbo switch and Setmul utility.

That's absolutely right, it is a 1994 build with a couple of holdovers. 😀 I don't usually do period correct. This is my only DOS primary machine and I need it to cover quite a lot in one build. There's a little bit more I can do to tune and scale its performance.

keropi wrote on 2020-03-13, 18:18:

very nice, love the build - it'a all quality parts!!!

Cheers, dude. It's a seven year long project at this point and I keep finding things to improve on. 😀

My Big Red Switch 486

Reply 6 of 37, by chinny22

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Only thing different that I would do is...um, nope got nothing.
love the PC and jealous of 1/2 its components!

Reply 7 of 37, by firage

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Some results from overclocking...

Overclocked to 3x40MHz:
Doom 51.1 fps (1461 realtics)
Superscape 3D Bench 1.0c 85.3 fps
PC Player Bench 27.0
Quake 13.2 fps (73.2 sec)

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In Duke Nukem 3D 1.3D, I'm getting 43 fps in the starting position on the roof. (Tseng optimized 320x200.)

It's a fast 486, man. 😀

Last edited by firage on 2020-03-26, 08:57. Edited 1 time in total.

My Big Red Switch 486

Reply 8 of 37, by CoffeeOne

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firage wrote on 2020-03-13, 11:04:
Promise EIDE2300Plus: I had high hopes for the EIDE4030Plus caching controller instead, but just couldn't get the performance ou […]
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Promise EIDE2300Plus:
I had high hopes for the EIDE4030Plus caching controller instead, but just couldn't get the performance out of it.
The EIDE2300Plus supports transfer modes up to PIO Mode 3 or MWDMA 2. No bus master DMA. Bases cycle times on system bus clock, i.e. PIO 3 should run at PIO 4 on a 50MHz bus. Requires a 7kB driver to enable transfer speeds above those of ISA based controllers.
If the adapter ROM is enabled, the controller will reduce the first 640kB of conventional memory by another 3kB, besides its UMB footprint; I have no need for it, because the motherboard BIOS already supports LBA without an extension and there's no other benefit in any measurements.
I've got a 2GB Transcend CompactFlash connected; something else might deliver the ultimate performance here, as it isn't even detected as MWDMA capable.

I am confused about the section about the vesa local bus multi-io controllers.
Both vesa local bus controllers with dedicated bios are crap?
They are not even a tiny bit faster (in IDE transfer) than an ISA controller?
So you use now the ISA controller, right?

Reply 9 of 37, by pshipkov

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Really cool rig.
Great job Firage !

@CoffeeOne
In my opinion caching controllers won't have much, if any, effect with CF storage.
From all 486 class motherboards and controllers that i messed with, Asus PVI seems to be the only one doing the PIO4 mode with real 10Mb/s transfer rates, which is at least on par with the toppest (tm) dog Fast SCSI VLB adapters from that time.
I will be interested to hear if others can expand on the subject based on their own experience.

Reply 10 of 37, by firage

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CoffeeOne wrote on 2020-03-23, 23:46:
I am confused about the section about the vesa local bus multi-io controllers. Both vesa local bus controllers with dedicated bi […]
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I am confused about the section about the vesa local bus multi-io controllers.
Both vesa local bus controllers with dedicated bios are crap?
They are not even a tiny bit faster (in IDE transfer) than an ISA controller?
So you use now the ISA controller, right?

I am using the non-caching EIDE2300Plus VLB controller and loading its driver. Speedsys is measuring a 6MB/sec linear read at 33MHz bus or 7MB/sec at 40MHz. (2-3 MB/sec if I don't load the driver, which is on a par with ISA.) I could likely do better (10-15MB/sec?) using something faster than this CF card and enabling MWDMA 2, with the driver. A VLB controller that does the same without a 7kB driver is definitely an improvement I'm interested in. At least you can load it high here with UMB's enabled - there's plenty of room having disabled the adapter ROM.

The caching EIDE4030Plus controller gets numbers above 16MB/sec in buffered reads and I'm sure its delayed writes smooth out the user experience a bunch. The problem is its slow "EIDE" interface. It's immediately apparent in linear read measurements being stuck at about 2MB/sec, which again you could hit with an older ISA controller. It is an absolutely *ideal* controller for disks that topped out at that 2MB/sec, less so if it's bottlenecking a 16MB/sec PIO4 disk.

My Big Red Switch 486

Reply 11 of 37, by firage

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Massive transfer speed boost from simply changing CF adapters, going from one random eBay adapter from China to another. MWDMA works now and it's a significant difference from the fastest PIO configurations available on the EIDE2300Plus.

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(Zero difference in non-storage benchies.)

My Big Red Switch 486

Reply 13 of 37, by pshipkov

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@firage
This is some great IDE perfomance for sure.
Better than VLB SCSI controllers in 10mb/s mode.
Can you expand on your experience with EIDE2300Plus ?
It has a bios -check, needs a driver - check.
What options it provides for its configuration ?
Thanks.

Reply 14 of 37, by firage

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Here's my scan of the controller's documentation for anyone interested:

Filename
manual_eide2300plus.zip
File size
2.36 MiB
Downloads
6 downloads
File comment
Promise EIDE2300Plus User's Manual
File license
Fair use/fair dealing exception

The back of the box sure promises™ a lot...
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pentiumspeed wrote on 2020-03-25, 19:29:

Show us the PATA to CF adapters of chinese and one that is fastest (photos)?

Cheers,

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The black one allows DMA, the green one didn't.

I guess many of them just are built without DMA support. https://us.transcend-info.com/Support/FAQ-326:

If you want to install a CF card that supports the DMA function on a motherboard, please check that your onboard CF socket or CF […]
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If you want to install a CF card that supports the DMA function on a motherboard, please check that your onboard CF socket or CF-to-IDE adapter supports the DMA function. You can examine if the following signal pins are connected properly. If yes, the socket or the adapter does support DMA function.

1.Pin 21((DMARQ) of IDE <-> Pin43 (DMARQ) of CF connector
2.Pin 27(IORDY) of IDE <-> Pin42 (DSTROBE/DMARDY/IORDY) of CF
3.Pin 29(DMACK) of IDE <-> Pin44 (DMACK) of CF

My Big Red Switch 486

Reply 16 of 37, by Intel486dx33

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Expensive sound cards but....

From my experience the Sound Blaster AWE64 ISA sounds just as good as all theses sound cards and has good game compatibility at
fraction of the costs.

Reply 17 of 37, by PC-Engineer

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Intel486dx33 wrote on 2020-03-27, 16:55:

... AWE64 ISA sounds just as good as all theses sound cards ...

No!

btw - @firage, very nice build and well thought out!

1994/1995 - Socket3 - ASUS SV2GX4 / POD 100MHz / 64MB / SCSI - Windows 95

Reply 18 of 37, by Intel486dx33

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PC-Engineer wrote on 2020-03-29, 14:08:
Intel486dx33 wrote on 2020-03-27, 16:55:

... AWE64 ISA sounds just as good as all theses sound cards ...

No!

btw - @firage, very nice build and well thought out!

Well, The reason Gravis Sound cards and Media Vision sound cards went out of business was because consumers found it to expensive and found better sound quality and compatibility in the Sound Blaster sound cards which are still around today.
Don't blame me. The consumers made the choice.

It's like a teacher. Is a teacher with a better voice a better instructor ?
Does a better voice make for a better human ?

What student want is to learn.
learn software and games.
That's what a computer is is a communication device. Sure you want good audio quality but you don't want to spend an "Arm and leg" for it.

I will leave you with these Gravis Ultra sound slogans.

Gravis Ultra sound - "Ultimate sound solution"
"Enhanced digital effects to any sound blaster"
"Improve your ears with out spending an arm and leg"

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Reply 19 of 37, by firage

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One of the best things about a real steel DOS machine is that you get to experience different sound cards. Each of the three sound cards and the external module is quite clearly preferable to an AWE64 Gold for their own set of games/demos/tracks. My choice here is to leave the cleanest SB16/AWE titles for a Win9x build that runs those late DOS games the best anyway.

My Big Red Switch 486