gdjacobs wrote:

Using the turbo switch in this way makes the machine something special. You, sir, have created a truly rare breed!

Thanks, the Turbo switch does add another dimension to slowing down. I'm still figuring out exactly what it does. On this board, it affects the K6 CPUs differently, and slows down the most for CPUs with on-die cache. Moreover, other Socket 7 boards with Turbo switch also behave differently, especially ones from Intel and VIA. Both these types react to Turbo less drastically.

carlostex wrote:

I would like to see this machine benchmarked by checkit as it gives Dhrystone/Whetstone scores.

For the following configuration: Baseline 1 (slowest for board), Tseng ET6100:

Dhrystones: 268-276
Whetstones: 1563000-157000

Is this what you are looking for? I can post more benchmarks as well - let me know if you prefer Checkit 2.1 or 3.0 for these results. I could also try the ISA Tseng ET4000AX...

CPU is slower than an 8088 at 4.77 MHz for this configuration and the FPU is significantly faster than an 8087. I'm wondering if anything used an FPU that would be speed-sensitive in this speed range?

Nice. I usually only use Checkit 3.0 but its nice to see the 2. If you can benchmark the other configurations it will be nice too.

Granted, a slower than 4.77MHz config won't be useful but it is certainly unique.

j^aws wrote:

Also of note is the ability to force an 8 or 16 bit bus; this comes in handy for slowdown using the video controller rather than the CPU. So you could create a graphics-bound setup instead of being CPU-bound.

R547 1.png

This is really interesting and I wasn't able to find anyone talking about this in my searches through the forums (unless I'm missing it). Everyone talks about CPU for speed sensitive games but they don't seem to mention VGA speed. I only first heard of this in your reply to my post where I was experiencing animations that were way too fast in Might and Magic 3 despite having my CPU slowed down to 386 speeds through SetMul/Cache because I am using a fast V3 card. I tried tinkering around with BIOS settings... shrinking AGP Aperture size and disabling some other stuff but it made no impact.

There are some other games I've played where the gameplay itself is smooth and nothing is broken but again certain animations move too fast. It is great to see your benchmarks and just how much of a difference these cards make in FPS despite these games being software rendered. The Voodoo cards can be downclocked but not past a certain point and only in Windows, not DOS.

I'd stick an ISA graphics card in there too but my only 2 slots are used up by sound cards. Maybe there are some early PCI graphics cards that perform just as slow as an ISA?

Great build you have here. From reading I had done in the past I was under the impression that Turbo headers on S7 Boards just changed the FSB to whatever the lowest available was.

infiniteclouds wrote:

I'd stick an ISA graphics card in there too but my only 2 slots are used up by sound cards. Maybe there are some early PCI graphics cards that perform just as slow as an ISA?

Keep in mind that that mixing ISA VGA with PCI/ AGP VGA isn't always possible; you need to be able to disable/ enable the ISA card somehow.

Regarding slow PCI cards, Rendition Verite cards are very slow in certain modes. I should benchmark some for comparison when I get a chance. Also, certain early PCI GUI accelerators come with separate VGA cores that are usually gimped (generally slow or on a narrowed bus), and these can be useful for slowing down, too.

infiniteclouds wrote:

Great build you have here. From reading I had done in the past I was under the impression that Turbo headers on S7 Boards just changed the FSB to whatever the lowest available was.

Turbo implementation varies on how the manufacturer designed the board and the chipset used. Sometimes people just attach the case Turbo switch to FSB jumpers on the board itself, but that's not really a Deturbo function. Besides, certain boards with actual working Turbo headers also behave as if FSB was being halved - there are many variations.

I should get back to finishing this project (sidetracked with my backlog). One thing I was considering alongside the Apocalypse 5D was a single-slot Voodoo 2 SLI card, but this card seems too long without using a riser cable of some sort. The other combination I was thinking of would be a PCI Voodoo 4500 and a standalone PowerVR PCX2 card - any thoughts on those setups?

I didn't think Voodoo 4s had good compatibility in DOS with 3dfx/glide patches making V2s or V3s, at most, work well. Wouldn't a PCI Voodoo 3 be better for a 6 in 1?

^^ I don't think I've tried anything for Glide in DOS using Voodoo 4/5, and I'm not even sure anything using these VSA100 chipsets would work?

For DOS compatibility, I think the order goes like this:

V1
V2
V3
V4/5

If I was to use a V4, I was considering DOS compatibility to be covered by a PowerVR PCX2. Although, I don't know what portion of DOS Glide games are covered by this - I suspect not many. I came across Glide games here:
DOS Glide Games List

Regarding V3 being better than V4 in DOS, at least for demoscene stuff using their VGA cores, I found the V4 more compatible. For example, the following uses 24bit colour in DOS and works for all available modes on a V4, but not on a V3 - Planet Logos T5:
http://www.pouet.net/prod.php?which=5553

Also, some demoscene programmes will not look right on a V3/ V4 unless the CPU is slowed down...

Candidates for the two PCI slots are these:

1) Obsidian X24 (V2 SLI) and Apocalypse 5D (PCX2)
2) Voodoo 4500 and PCX2

Option 2 would be the easiest to install and fastest, and Option 1 would be the most compatible but harder to physically install.

On a machine that's already all about max compatibility with its uber flexible speeds I vote for option 1.

infiniteclouds wrote:

I didn't think Voodoo 4s had good compatibility in DOS with 3dfx/glide patches making V2s or V3s, at most, work well. Wouldn't a PCI Voodoo 3 be better for a 6 in 1?

I did a test a while back that included both PCI and AGP Voodoo 3 3000 cards.

DOOM was way faster with the AGP card than with the PCI card. Probably (definitely) has something to do with the PCI bus limiting the throughput. Not that the fps was bad with the PCI card.. just not what was expected as I have always heard that it doesn't matter for the Voodoo 3 / 5 cards if it is PCI or AGP.

R547 is manufactured by M-tech. Was "Rise" the name they used in Asia or something?

cyclone3d wrote:

infiniteclouds wrote:

I didn't think Voodoo 4s had good compatibility in DOS with 3dfx/glide patches making V2s or V3s, at most, work well. Wouldn't a PCI Voodoo 3 be better for a 6 in 1?

I did a test a while back that included both PCI and AGP Voodoo 3 3000 cards.

DOOM was way faster with the AGP card than with the PCI card. Probably (definitely) has something to do with the PCI bus limiting the throughput. Not that the fps was bad with the PCI card.. just not what was expected as I have always heard that it doesn't matter for the Voodoo 3 / 5 cards if it is PCI or AGP.

I did some testing a while ago and the times when there were any significant differences between the AGP and PCI versions was when the AGP bus was overclocked. Do you recall the setup used? Certain FSB speeds would overclock AGP on certain chipsets. You can also overclock the PCI bus, too.

Anonymous Coward wrote:

R547 is manufactured by M-tech. Was "Rise" the name they used in Asia or something?

I thought it was the other way around - Rise being the parent company and M-tech being the Western subsidiary. The 'R' in the Rxxx series representing Rise?

Regarding the build itself, I've been sidetracked but will get around to finishing it. I've shortlisted a few nice AT cases. My choice of PCI card lengths are limited due to motherboard layout, so I've picked up some PCI riser cards.

I'm thinking of ways to mount cards securely in an appropriate case. This can leave me to use 6 ISA cards alongside 2 PCI cards. Would using both the shared ISA/ PCI slots cause any issues? I'm not sure it would.

Trying to get some progress on the build, so I thought I'd try to dig up a case and picture the final result. I have a few AT beige boxes - two mid-sized tower cases, one with MHz LCD display and a Turbo button, and another without. Also a desktop case with a Turbo button but no MHz display. Since they are buried in boxes, found this case nearby:

Might be okay for this build - thoughts? It's a bit tatty at the moment.

It's easy to forget that Turbo switches weren't present in the earliest case designs.

j^aws wrote:

Might be okay for this build - thoughts? It's a bit tatty at the moment.

I'm a big fan of the original XT case. One issue is that half-height drives require an additional mounting kit, which can be a bit pricey on eBay. Not sure if someone made a newer kit for that or if your DIY skills can make that a non-issue. The XT PSU may be low-powered for your build and if so you'll need a replacement PSU that has a power switch in the same position, or something where you can rig a switch elsewhere. There's also the lack of a turbo switch and front-panel speed LED, but you knew that already. There's a little panel on the back of the XT that you can drill mounting holes for anything you might need, so that's an option. Alternatively, if you're planning to use half-height drives you might not need four bays for media. In that case, you can build your own front panel and go nuts adding features not otherwise included on the case.

MrSmiley381 wrote:

j^aws wrote:

Might be okay for this build - thoughts? It's a bit tatty at the moment.

I'm a big fan of the original XT case. One issue is that half-height drives require an additional mounting kit, which can be a bit pricey on eBay. Not sure if someone made a newer kit for that or if your DIY skills can make that a non-issue. The XT PSU may be low-powered for your build and if so you'll need a replacement PSU that has a power switch in the same position, or something where you can rig a switch elsewhere. There's also the lack of a turbo switch and front-panel speed LED, but you knew that already. There's a little panel on the back of the XT that you can drill mounting holes for anything you might need, so that's an option. Alternatively, if you're planning to use half-height drives you might not need four bays for media. In that case, you can build your own front panel and go nuts adding features not otherwise included on the case.

Thanks for the insight - this is really helpful as I don't normally work with XT type cases. There are a number of pitfalls that are easy to miss. Another pitfall that just occurred is that the motherboard layout for the CPU would mean its position falls around the inner bays, which means I may have to sacrifice them. I try to get cases with 4 half-height bays to add numerous expansion options. Hmm, I like the idea of this iconic case that started the PC standards we have today. May have to reserve another board for it with a more accommodating CPU layout...

So I tried booting the R547 board after a long hibernation period and it gave me scares as it wouldn't POST. The fan kept spinning with no boot screen. Some random jiggling of inconsequential wires suddenly brought it to life. I must say the POST beep sound must be the most musical sound to builders ears! And I'm reminded how flaky old parts can be and how they can die a silent death. I wonder if cold booting syndrome is a real thing?

After this scare, I'm posting the boot screen and BIOS string for reference and posterity:

Choosing the case seems to be the hardest part. I have in mind a traditional beige AT case. However, the cards I want to use with motherboard layout is causing me to look at modern HTPC ATX cases. So far, the video cards I want to use:

PCI:
- Apocalypse 5D (PowerVR PCX2 and Tseng ET6100)
- Obsidian X24 (Voodoo 2 SLI)

ISA:
- Tseng ET4000AX
- Reelmagic Lite (MPEG1)

4 ISA soundcards

8 total cards, 7 slots on motherboard. If I use a PCI riser card, I'll release the shared ISA slot. The Obsidian would need to be on the riser due to being too long for the board layout. I'm thinking of a 7+1 ATX case like:

You can see the 7 normal slots and 1 raised one above them. Anyone use these types of cases before? How would the top slot hold out to a long Voodoo card? It would lack the motherboard PCI slot to support it. What model cases have the above layout?

New arrival!
Bought a HTPC case for its slot layout to install the Quantum X24 and large number of external bays.

Nice and clean front, it's a Silverstone GD series with a brushed aluminium panel - looks nice IRL:

Look at all those bays! Reminds me of old school desktops without front fans. The motherboard has on board USB, so could use those front access ports. Need to figure out how to swap out the momentary power on switch with a toggle one that comes with AT PSUs!

Nice and spacious inside with ATX layout standoffs. Now, I wonder how many extra holes I'd need for a baby AT layout? The fewer I need to drill the better... I'm not a fan of working with metal! Might need to upgrade my drill as it's rather shite.

I need to get this Quantum X24 installed with the awkward motherboard layout and CPU placement:

Fortunately, there may be a way to suspend it in the case...

A test run to see how cosily it fits... I wonder if I'd need to give it extra support at the end to avoid it warping?

Further investigations in expanding the build with an ISA riser card:

Secondary plans to possibly hack this into the case to extend the ISA configuration by a further 3 slots (9 ISA + 2 PCI).

Eyeballing the install seems to be feasible.

Birds eye view, which shows the PSU would need to be on the other side and mounted accordingly. A baby AT motherboard is fairly narrow, so maybe possible?

How to secure the brackets for the riser cards? This view gives some further insight.

And this cutest of sound cards has arrived! Thanks Matze79!

This Tandy sound card will provide pre-OPL2 music for the oldest games to run on this build. If I can use the riser card, I'd stuff more 8 bit cards into this case... Hmm, which cards to include?

So, taking a break and resuming a build is both a blessing and a curse; I found a miscellaneous box with this video card and no info:

I don't recall buying this, although it looks like I put it aside for further investigation. It's a CGA card with a 9pin DSUB connector and what looks like an RF output? I can't test it currently as my Eizo CGA/ EGA/ VGA multisync monitor is dead (reminder to find a repairer).

Anyone know anything about this card? I'm curious if I could still upgrade what looks like empty video RAM for CGA? Or are they just empty ROM sockets?

Just wondering, have you tried a few XT speed sensitive games like Striker on it at XT speeds. Would be interesting to see if the slowdown to this degree actually works for real world programs.

canthearu wrote:

Just wondering, have you tried a few XT speed sensitive games like Striker on it at XT speeds. Would be interesting to see if the slowdown to this degree actually works for real world programs.

Are you referring to this game:
https://www.youtube.com/watch?v=oLP6y58RyRM&app=desktop
Strike is an old 2D scrolling shoot-em-up. The above is running on a modified 386 board with a slow crystal clock at around 5 MHz. I'm not sure on what the correct speed the game should be running at. That's a choice I suppose with speed-sensitive games where games could be played at a speed favourable to the user. Are there any videos running on an IBM XT for reference?

I have tested Striker before. I've ran the game at the above speed and other speeds in this ballpark without issues on this K6-III+ CPU. It would be good to test other games as well - any suggestions?

When the build is complete, I might test a bunch of games in chronological order from 1981 to 2000. And maybe make some simple GIFs highlighting a range of speed-sensitive games through the ages...

Did some more investigating to convert the case fully from ATX to AT. Firstly, I was looking to change the power switch from a momentary switch and install a toggle switch from an AT PSU.

Silverstone case with fans and cage removed - very spacious.

You can see the current switch just popping out of the large circular housing. Needed to remove the hot glue.

Couple of pictures with the switch removed.

The AT switch doesn't seem like it will be easy to mount.

An easy win is seeing if the ATX switch could be replaced with another one housed identically, but toggles instead. Its housing is 8x8x8 mm, and the actuator is 5 mm long. Anyone know where I could get one offhand? And it also needs to be able to handle the current and voltage as well. I'll be using an ATX PSU conversion with the switch attached to its 20pin connector.