Mac IIvx questions

[maditgeek]

Hello I recently acquired a mac iivx

fearing it might need a recap job but turns out no battery leak and no mobo damage that I see (other than being dirty)

and it turns on and chimes and runs currently system 7.5.5

it has 68mb of 70ns ram- I do have 32-bit addressing turned on.

it has the full 1mb of VRAM (also 2x 512k 70ns)

I'm using a seagate 7200rpm 9GB HDD with a scsi 68-to 50 pin adapter

my question is this:

While I'm fully aware the iivx is known for being kind of a dog due to the 16mhz bus I didn't think it would be this bad

even playing very early mac games like Oregon trail and the "256 color" version of Leisure suit Larry1-both are very laggy Larry moves slowly in the bar but then outside bar he walks a bit faster (not to mention the long load times in between scenes)

and oregon trail even lags while hunting

I'm running the mac at 640x480 at 256 colors

so my question is this: is there any speedups? other than clock crystal replacements to bump up the bus speed to higher than 16mhz? Should I be running system 7.5.5? I read 7.6 isn't optimized for 68K macs would upgrading quicktime help (my understanding is its a system component)

and if I where to actually find a PDS accelerator   card would it even help due to the 16mhz bus?

one last thing: I also noticed that while the VRAM was upgraded with 2x 512k sticks-they are not matching. both are 512k and both 70ns but one stick has 2 chips on it and the other has 4-I do have the original Apple 512Kb kit of vram sticks-would I be better off?

 

[joshc]

Welcome to the forums.

First off, you should still recap this machine - even if the original caps "look" fine - its unlikely they will be. I've removed lots of caps that look fine, to find they were leaking underneath. At this point, the IIvx is ~29 years old so the original caps will be due for replacement by now.

The IIvx originally shipped with System 7.1. The max OS it can run is 7.6.1, but I don't recommend it.

Downgrading from 7.5.5 to 7.1 or 7.1.1 (System 7 Pro) is my recommendation, the machine will run better on either of those versions. This won't specifically make your games run faster, but it will help with boot times and general responsiveness/speed in the Finder.

I don't think swapping the VRAM for the other stick you've got will make a difference, as it sounds like you can already run at 256 colours.

The 16 Mhz bus makes the IIvx roughly equivalent to a 25 Mhz IIci (some references state it is slightly slower).

The PDS slot is limited by the same 16 MHz bus. The PDS slots on Macs are machine-specific* and so you will run into compatibility issues if trying to use an accelerator for another machine, plus the fact that an accelerator will be very hard to find.

Edit: It's been mentioned that an adapter can be used for use with other cards, see Daniel's post below mine.

In terms of acceleration, the other option is upgrading the logic board to that of a Quadra 650 which will fit inside the IIvx case. This gives you a 33mhz bus. Finding a board might not be easy but might be worth investigating further.

I am attaching Apple's developer notes for the IIvx here as you may find the information useful:

Accelerator Slot 1
The accelerator slot introduced in the Macintosh IIvx provides all the signals necessary to support an auxiliary microprocessor. This slot is similar to the Macintosh IIci cache slot, but does not include some of the cache control signals. Most of the signals on the accelerator slot are connected directly to the corresponding signals on the 68030.

▲ WARNING
The Macintosh IIvx accelerator slot is not compatible with
processor-direct slot (PDS) cards designed for other Macintosh computers. Although the same 120-pin connector is used for the PDS on some Macintosh models, the electrical signals are different. Installing a PDS card in the Macintosh IIvx accelerator slot may damage both the computer and the card.

View attachment Mac_IIvx.pdf

 

[Daniël]

Welcome to the forums.

First off, you should still recap this machine - even if the original caps "look" fine - its unlikely they will be. I've removed lots of caps that look fine, to find they were leaking underneath. At this point, the IIvx is ~29 years old so the original caps will be due for replacement by now.

Can confirm, I had a Performa 600 (basically the inbetween model, it has the faster CPU clockspeed of the IIvx, but the lack of cache of the IIvi), that wasn't working due to really leaky caps. It was still relatively fresh (visibly wet and no corrosion), but enough to stop it working (likely the EGRET got shorted out). A recap is necessary in the short term.

The PDS slot is limited by the same 16 MHz bus. The PDS slots on Macs are machine-specific and so you will run into compatibility issues if trying to use an accelerator for another machine, plus the fact that an accelerator will be very hard to find.

This is not entirely true. The Sonnet Presto 040 that was a surprise in my P600 will work on other Macs like the IIci, IIcx, IIsi, etc., though some of these Macs need an adapter. The IIvx/IIvi/Performa 600 line is generally fully compatible with accelerators for those machines without the need of an adapter.

I can say though, that this machine still feels relatively slow even with the 040. I would have gotten a PDS adapter for my SE/30 to use this in, had it not been that the Sonnet is one of the accelerators that hasn't been managed to get to work in an SE/30

Don't have any other Macs it's directly compatible with (I have a working IIsi board I plan to put in an ATX case, but that needs an adapter for the accelerator to work), so it'll live in the P600 unless I happen to get another compatible Mac, or the Sonnet is made to work in the SE/30.

 

[joshc]

Thanks for the correction @Daniël Oosterhuis - that will teach me for speaking about a machine I've never used or owned! :embarrassed: I've edited my original post to not cause further confusion...

 

[maditgeek]

thanks for the information

Yes, I was preparing for the fact that I probably need to recap the mac iivx mobo sooner rather than later. (actually I should of said there is a white spots around the edge of the nubus slots-that might be corrosion but I wouldn't think that would show up as white-kinda looks like baking soda around that slot) so I was somewhat surprised that it currently works. (I did pull the PRAM battery)  I got the original box and the original accessories that came with it..so I do have the system 7.1 floppys that it shipped with (I'm the 2nd! owner original owner got it in 2-16-1994. Which I find interesting as I researched and found out Apple stopped production of this mac in 1993 but the original shipping label is still on box and it looks like it went from apple to a reseller of some sort)

I am discouraged by @Daniël Oosterhuis post that even a 68040 upgrade card didn't do much. I was kinda thinking (or hoping) that this mac would be close to a Mac LC III in performance but it really looks like that 16mhz bus is going to anchor this mac, unfortunately. 

I do not know how to solder-but I have a friend that does (he is hours away unfortunately) I'm thinking about maybe posting this mac (with pictures showing the white spots on nubus slots) in the trading post with a nice firm warning that its running on Apple original caps still.

I could learn how but I rather not practice on this mac.-it is working and booting to system 7.5.5 RN and my great fear is I will brick it.

 

[Daniël]

I should clarify that it feels relatively slow for an 040 Mac. I've never used an LC III so I can't comment on which one would be/feel faster. But I do think you could probably get a better 68k Mac, either '030 or (LC)040, for the same price as an accelerator would cost, if not less. I got lucky in that the card came with a €30 Mac, I wouldn't have spent the average price on one of these cards with the intention of putting it in my Performa 600.

 

[jessenator]

Architectural differences/limitations of the various budget-home models aside*, I found this chart's info interesting.
a 68030 will perform about 18 MIPS at 50 MHz
a 68040 will perform about 44 MIPS at 40 MHz

So quite the IPS jump with that generation, so even a base 25 MHz 040 will outpace (just in pure numbers here), say a PowerCache'd 030 machine by a margin (4 MIPS). Now before you start nitpicking, *of course there's additional considerations as far as which Macintosh is faster: floating point operations, and data buses, L2 cache, framebuffers/graphics hardware, etc., but I'm just keeping it simple (for my own brain to comprehend) and talking about the CPU only, in and of itself.

This all matches up with my Feelometer™ with playing 68k games on a accelerated IIci versus a Quadra 700 or on a 650: viewing tile and color cycling in particular on titles like SimCity 2000, for example. But even in an upgradeable machine, the difference was incredible: I had a stock IIsi and later I had it running with an adapted Turbo 040—night and day, really. Wish I hadn't had to sell it, but needs must, spilled milk and all...

 

[beachycove]

Back when dinosaurs roamed the earth and I had all my own teeth and a full head of hair, I owned a Performa 600. I used it for years and it gave me reliable service within its limits. I wrote a couple of books on it, so I can’t complain I suppose, but I do recall that in later years, 7.5.5 brought it to a crawl.

One of my abiding memories was going to the University computer labs around 1993 and starting up one of the institutional LC475s. For some reason I needed to access something in MacOS that I could not on the 286 I had in my office at the time. It was my first encounter with an LC475, and I thought it was a dinky little thing — until it got going and I saw the enormous difference between it and my own P600. 

The IIvx is a better machine than the P600 (L2 cache and 68882), but not by much. You really will do better in 7.1, and you ought to see a big difference with an accelerated Nubus card as well.

 

[maditgeek]

@jessenator haha that's how I gauge all my vintage pcs too by "feel" (I have a IBM thinkpad 770 and a powerbook g3 pismo 400mhz)

I figured there would be a jump to '040 from '030. but WOW that is HUGE yeah I know MIPS is not the be all end all but that level of efficiency improvement will be "felt"

the problem is as others have pointed out in those posts. accelerator cards are hard to find and when I have come across them-its way more than what I paid for this mac iivx!

I have played simcity 2000 on this mac with the "i wish i was" extension turned on to "fake" a '040 cause I thought it might require a '040 (looks like it don't turns out) and its a..slideshow lol if I run it on a RAMdisk (I have 68MB to play with ) simcity speeds up to..allllmost playable

boot times/finder responsiveness is fine by me in system 7.5.5 (probably because I have enough RAM) its just..running applications..even stuffit after its done takes a bit to close itself out once its doing extracting something.

system 7.1 will help my mac sounds like but not by enough.



 

 

[bigD]

My Quadra 700 feels *substantially* faster than my 50MHz IIci. The benchmarks confirm this, especially when it comes to FP. The '040 is simply a much faster chip on a clock for clock basis.

That said, there are few things in vintage computing more satisfying than running System 6.x at 50MHz.

 

[maditgeek]

Thanks to all. I'm going to put this on the trade post. After I get a SCSI CD drive delivered to me (the 16x it came with read my 7.5.3 cd and then refused to even spin up ever since) I was going to get a centris 610 on ebay until I got sniped and I wound up with this maciivx instead. I learned that a '040 is way faster. I know it was quicker but did not realize the gap

 

[maditgeek]

A quadra 660av would be a big upgrade then, correct? (I may have a line on one)

 

[joshc]

A quadra 660av would be a big upgrade then, correct? (I may have a line on one)

That will give you 25mhz CPU and a 25mhz bus. Max ram is 68mb. Just beware, the plastics on those cases are brittle now and the clips to remove the lid often break off. It's not necessarily a reason to not buy one, and the same also applies to other models of the same age, just something to be aware of.

 

[beachycove]

It's very, very hard to get a Nubus card adapter for one of these. Just saying.... Mind you, I have one that will be going on eBay shortly.

Having said this, a Q660 already has Ethernet and very decent video. They are also interesting machines historically, because of the form of multiprocessing involved in their peculiar architecture.

As to performance, any 040 machine will offer a significant performance boost over a IIvx. The limits of the operating system will be the same, of course, but the particular limitations of a IIvx will no longer be a factor.

Other options: An LC475/ Quadra 605 is a nice machine. A Q650 is mostly metal, like the IIvx (same case), which in the Mac era we are talking about is very good news because of rotting plastics problems. It is also much more expandable. Either would likely be a good deal cheaper than a 660.

As also noted, a logic board from a Q650 would fit in your IIvx case (though you would need to open up an Ethernet port in the rear), as would a 7100 board (with a little more surgery). Those were official upgrade options back in the day, and might still be the cheapest option for you.

 

[jessenator]

Another vote for the 650 (even a Centris). The other added bonus with them is their boards came with tantalum caps from the factory, just like the Quadra 700. So unless you really want to replace them with polymer caps for some reason, it should be a maintenance free logic board.

Just because it's a Centris 650 doesn't necessarily mean it's got a 68LC040 in it. ---They have an SMD-selectable ID on the motherboard that tells whether it's a Centris or Quadra 650, or a Quadra 800 (see Wombat tidbits on AppleFool), as it's the same board with slight component variation.---

My Centris 650 has a full 040 and AAUI ethernet, but it's 25 MHz. A Quadra 650 and 800 will be 33 MHz.

I can't recall, but there was some way to know what had a full 040 or not... Still, a full, 25 MHz 040 isn't as unobtainium as some make it out to be, if you wanted to swap later down the line.

I saw a C650 on eBay recently for a decent price, even was shown booting, so the PSU is still good.

 

[cheesestraws]

I can't recall, but there was some way to know what had a full 040 or not

From what @Paulie was saying yesterday, if it has 4MB RAM on board it came with an LC040, if it has 8 it came with a full 040.  Mine has 4MB and is an LC040.

But yes, the 650 in either incarnation is a good machine.

 

[Solvalou]

When I bought my IIvx it had the original caddy type CD-ROM drive, 64MB of RAM (like yours) and fully populated VRAM.

I've since swapped out the RAM for smaller ones (was wasted on that, was better used in my 040 IIci), added a Radius Thunder IV GX and a bigger HD (1GB).

It sounds like your IIvx, despite it being a "black sheep" for 68K owners, appears was very much loved, just like my machine.

I wouldn't write off later OS' though. Mine happily runs 7.5.5 okay but I keep my extensions to a relative minimum. That said I am certain 7.1 would be pretty zippy if you do decide to downgrade. Just my pennies thrown in.

They don't seem to suffer so much for cap issues like other machines do, but I do agree that you should do something about it if funds and/or time permits. If not, at least take the board out and give it a clean with a gentle brush in soapy warm water.

Good luck, don't forget to show pictures!

 

[maditgeek]

Tokyo racer I do have pictures on the trading post here. It's about a $20 difference between quadra 660av and a centris 650. (Quadra more) though the centris has a nubus rj45-coax eithernet card in it. 

 

[jessenator]

if it has 4MB RAM on board it came with an LC040, if it has 8 it came with a full 040.  Mine has 4MB and is an LC040.

Ah! Good eye there, @Paulie, that makes some good sense:

Both of my boards have 8, and came with full 040s.

I wonder, could you corroborate: does your 4MB Centris have 8 soldered chips? I think they would just do that rather than 16 of smaller capacity DRAM... but you never know. Also, not surprising, but the Quadra has faster RAM (I think the 800 has 60 ns...)

Even still, @maditgeek if we're looking at the same listing, that section of the board is beneath the drive chassis/cage (just beyond the furthest-hidden DRAM socket) and not visible from the photos -_-  Yeah, having a twisted pair card in the machine definitely does save one from the additional (small) expense (and dongleage) of buying an AAUI adapter.

Edit: hmmm, unless they did 16x256 instead of 8x512, that might actually be an 8 MB Centris board, and by our observations, a full 040 on board. Hmmm..