SMP Pentium box with AGP? (Was: I have a plan...

[Raven]

Some day I'd like to do this...

Build a Pentium-based box that can run a modern OS (in this case XP32 as a minimum target) and modern games (meaning it would require a very powerful AGP card, and the fastest AGP slot we can find). The problem is that AGP slots and SMP are not friends. I'd like to get four 300Mhz or so (if the mobo is capable, might achieve 400Mhz) Pentiums together in SMP to achieve the kind of speed necessary (and by modern, note that I don't mean things like Crysis - more like Command and Conquer Generals).

Why do this at all, ever? Pentiums were the last 16-bit optimized CPU (if someone knows otherwise, perhaps some AMD CPU, etc., please do tell me) - for all intents and purposes a very fast dual core 486. DOS feels wrong on anything newer, and this would be a hybrid box that dualboots between DOS and the modern OS, perhaps 9x as well (triboots are fun).

I've thought about this in the back of my mind for about a year now to come up with the above guidelines, but didn't persue it because I'm not sure a quad-Pentium mobo exists, or ANY SMP Pentium with an AGP slot. Anybody ever see either of those items?

If not, how feasible do you think it would be to add an AGP bus and slot to a motherboard? I doubt anybody here would help me do that even if I paid them, but I'm just curious how possible it is.

This is all speculation and planning, keep in mind - I've no money to fund this project at the moment, just getting some ideas out there to see what people say.

 

[mbbrutman]

Some day I'd like to do this...

Build a Pentium-based box that can run a modern OS (in this case XP32 as a minimum target) and modern games (meaning it would require a very powerful AGP card, and the fastest AGP slot we can find). The problem is that AGP slots and SMP are not friends. I'd like to get four 300Mhz or so (if the mobo is capable, might achieve 400Mhz) Pentiums together in SMP to achieve the kind of speed necessary (and by modern, note that I don't mean things like Crysis - more like Command and Conquer Generals).

Why do this at all, ever? Pentiums were the last 16-bit optimized CPU (if someone knows otherwise, perhaps some AMD CPU, etc., please do tell me) - for all intents and purposes a very fast dual core 486. DOS feels wrong on anything newer, and this would be a hybrid box that dualboots between DOS and the modern OS, perhaps 9x as well (triboots are fun).

There is a big difference between a processor that is superscalar (multiple pipelines) and a dual core machine. The classic Pentiums have two pipelines, and they are not symmetric - they each do different types of instructions. The classic Pentiums also do not do any sort of hardware threading. So while a classic Pentium might be able to knock out two instructions in the same cycle, it is not capable of running two instructions from two different threads of execution at the same time. In contrast a dual core machine is really an SMP on a chip - two independent CPU cores, each of which is capable of running independent threads of execution. Except for a shared resource like a cache, they are functionally equivalent to stand-alone CPUs. (And in some ways better, when locking or sharing of the cache data is possible.)

If you want a high end 486, then have one. If you want a high end Socket 7 box, those are available too. And if you want the latest hardware to play current games on, then have that too. But don't try to shove all three in the same box, unless you are planning on emulation. There comes a point where a particular technology gets maxed out, and then that's it - you need another technology.

I've thought about this in the back of my mind for about a year now to come up with the above guidelines, but didn't persue it because I'm not sure a quad-Pentium mobo exists, or ANY SMP Pentium with an AGP slot. Anybody ever see either of those items?

If not, how feasible do you think it would be to add an AGP bus and slot to a motherboard? I doubt anybody here would help me do that even if I paid them, but I'm just curious how possible it is.

This is all speculation and planning, keep in mind - I've no money to fund this project at the moment, just getting some ideas out there to see what people say.

AGP is a chipset issue. If the chipset does not support AGP, then the machine doesn't have AGP capability. (There is no amount of money in the world that will change that now.) The Wikipedia article for AGP lists Pentium 7 chipsets that have AGP support; according to the authors none of those chipsets were from Intel. (Look for VIA.)

If I read your post correctly you are looking for a Socket 7 SMP system with AGP. There were Socket 7 systems with AGP. I don't think I've seen one that has two or even four sockets though. Especially if we are restricted to non-Intel chipsets - those were not targeted at the server market.

 

[FishFinger]

Putting multiple CPUs together doesn't make software run any faster unless it was specifically written to use multiple CPUs. All those games will only use one CPU, so the others will just be sitting idle, not making it run faster.

 

[Anonymous Coward]

I wouldn't waste your time with AGP on Socket7. It works about as well as PCI did for 486 based machines. A good dual socket 7 board is hard enough to find as it is. You'd be much better off with a late model PCI graphics adapter.

 

[Unknown_K]

AGP was ok on Super Socket 7 boards.

 

[NeXT]

True SMP boards with an AGP slot didn't surface until the ATX Socket 370 days. As mentioned above, by the time AGP came around, there was really no point on putting an AGP socket on a board that had only two regular Socket 7 processors because there was no advantages to be made.

 

[Dave Farquhar]

The other problem was that Super Socket 7 didn't have SMP support. I don't remember all of the details anymore, but something (perhaps patents) kept AMD and Cyrix from implementing Intel's SMP in their CPUs. They adopted a different method, but then none of the chipsets supported it, so the point was moot.

By the time AGP came around, Intel was committed to the P2 and Slot 1. So dual-CPU machines with AGP would be either Slot 1 or Socket 370. Intel wasn't too happy about the dual Socket 370 machines, because they didn't intend for Celerons to be used in SMP setups. I knew a fair number of people who did it though, once those boards appeared. I probably still have my Abit BP6 board somewhere. I think that board was prone to bad caps though, so I don't know if my caps would have held up.

 

[gslick]

I have a bare Asus P2B-DS in my spare parts bin. That's a dual Slot 1 motherboard with the Intel 440BX chipset with an AGP slot. It's probably been at least 10 years since I had that motherboard up and running.

 

[glitch]

You can find dual Pentium Pro boards, but I've never seen a dual socket PPro board with AGP. You can certainly run Windows XP on a Pentium or Pentium Pro system...it's not very fast, but with enough RAM it's marginally usable. I ran a 200 MHz Pentium-MMX laptop with 64 MB RAM with Windows XP for a little while at the end of high school (2004ish)...not great!

 

[Anonymous Freak]

You are not going to find an SMP Socket 7 with AGP. For one simple reason: SMP at that time was basically purely a server/workstation feature. There were no 'mainstream' SMP boards. By the time SMP became available on even high-end/specialty 'mainstream' boards, Socket 7 (even Super Socket 7) was long obsolete. Slot-1 and Slot-A were the mainstream at the time, and if you're going to go for a high-end (dual CPU) system, you weren't going to bother with a dual CPU ancient chip which was outrun by the then-current single-CPU system.

There were plenty of dual CPU "workstation" boards when AGP first came out, I had the Intel DK440LX, which was a wonderful dual-CPU board. But it was, of course, Pentium II.

 

[Raven]

I wouldn't waste your time with AGP on Socket7. It works about as well as PCI did for 486 based machines. A good dual socket 7 board is hard enough to find as it is. You'd be much better off with a late model PCI graphics adapter.

I don't really know why I didn't consider that - PCI adapters might not be as fast as AGP but they can most definitely achieve the stuff I'd want from this setup.

Dropping AGP, that leaves us with - is there a Quad-Pentium board with PCI?

There is a big difference between a processor that is superscalar (multiple pipelines) and a dual core machine.

Quite aware of that, which is why I worded it "for all intents and purposes". I've researched the CPU architecture of the 486, Pentium, and clones of both in-depth.

 

[Unknown_K]

There are 4x and 6x Pentium Pro systems out there with PCI slots (ALR/Gateway made one). What exactly you would do with one I have no idea.

 

[mbbrutman]

Quite aware of that, which is why I worded it "for all intents and purposes". I've researched the CPU architecture of the 486, Pentium, and clones of both in-depth.

If you've researched and understand the concepts, then "for all intents and purposes" there is no way to mistake a dual pipeline CPU for a dual core CPU. It makes no sense.

What I believe that you were trying to say is that one CPU is so much faster that it looks like multiples of something else. That makes more sense than trying to equate two threads vs. two cores.

 

[Raven]

I was equating the performance, not the actual internals - a P75 is about as powerful as an Am5x86-133, and so on. Sorry if I made that sound like a display of ignorance.

There are 4x and 6x Pentium Pro systems out there with PCI slots (ALR/Gateway made one). What exactly you would do with one I have no idea.

Pentium Pro is exactly what I don't want. The *Pentium* is the last 16-bit optimized CPU. The Pentium Pro is the beginning of the focus on 32-bit, and a huge lack of 16-bit optimization. They are also the first chip to use micro-op translation instead of just directly executing the instructions as-is. Between these two things (I don't know which is responsible), it just feels wrong to me when running DOS. Not noticeable to most people, but it bugs me it feels sluggish, but it does turn out faster when you take a higher enough clocked post-PPro chip (I used 1ghz), so it's not actually slower.. IMHO (I realize this is different for different people/interests) if a PPro can do what you want, you might as well jump all the way to Pentium III, because that's the last platform to support SB-compatible PCI cards (there may be a FEW newer ones, but not that I know of) and it'll perform the same with 16-bit titles, but do more with 32-bit ones. I, in fact, had a Pentium III DOS box for a while as my main retro box, and I downgraded for the snappiness that a 486 or Pentium provided in contrast.

The Pentium is unique because it's the fastest 16-bit optimized x86 chip, the clones don't even outperform the highest official chips (266Mhz Tillamook mobile, which is very overclockable if you find a desktop-converted one like I have). IDT Winchip, Cyrix chips of the era, etc.. they all pale in comparison.

If I got my hands on a dual Pentium or quad Pentium system (again *not* PPro), I'd max it out in RAM and CPUs (shoot for 512MB RAM and 4x300-333Mhz) to try to equate to a midrange XP system from around the SP1 days. If you blindly total the CPU speeds, ~1.2ghz effective speed (though I know it doesn't work that way, but no way to really know how it would perform before I see one). Let's assume that there's a huge hit to performance due to lack of 32-bit optimization and dock the speed to 800Mhz. That's still fast enough to run XP smoothly. This gives a 16-bit optimized machine capable of playing DOS games and such the ability to run modern software (or close to it) and browse the modern web, interact with modern computers on the network, etc.

As I say often, I like to push hardware to it's limits - including whole hardware platforms - in this case the Pentium platform. I'd just love to see what it can do, create a monster, etc. :D

 

[Old Thrashbarg]

The *Pentium* is the last 16-bit optimized CPU.

No it wasn't. One of the primary reasons behind the creation of the Pentium II was to fix the PPro's shortcomings in 16-bit performance, thus making the P6 core viable for consumer desktops.

 

[IBMMuseum]

I think you will need to consider a good PCI video card in an SMP Pentium system. As Mike points out, this server-class level wasn't really targeted at video. Even there, I wonder how "modern" of OS you can go to.

I've seen up to six Pentiums together with a gig of RAM (or five CPUs, and 2Gb of RAM). You can even mis-match CPUs cards on it. Eight slots of microchannel and PCI.

The Server 720...

Base Cirrus Logic video, but you could put in PCI video...

 

[Unknown_K]

People give the PPro a bad rap running 16 bit code. Granted it was super expensive when it came out and was built to run 32 bit code, but it also had a ton of cache and was fast at 16 bit anyway (just not cost effective). These days a PPro doesnt cost $2K a chip so you don't feel bad running it on 16 bit code. We are talking multi processor anyway and a PPro could have many more CPUs then the rare dual Pentium machines.

 

[Old Thrashbarg]

People give the PPro a bad rap running 16 bit code. Granted it was super expensive when it came out and was built to run 32 bit code, but it also had a ton of cache and was fast at 16 bit anyway (just not cost effective).

And unfortunately, that's a greatly misunderstood point. It's not that the PPro was slow at 16-bit, it simply wasn't better at 16-bit than the P54 Pentium (and was slightly slower than the later PMMX chips) at the same clockspeeds. Sure, that made a bad price/performance ratio for a general-use desktop chip at the time, since the 32-bit performance mattered considerably less in consumer-level applications, but considering that the things can be had dirt cheap these days, that point really doesn't matter anymore.

 

[luckybob]

these are the "gaming" systems that I have. Some are fully done others are still in the hopes and dreams section.

#1 Socket 3 monster; still in the planning stages. think "ultimate" 486.
#2 socket 7: Asus P5A; AMD k6-3+ 550; 512mb ram; ATI rage fury maxx; win98
#3 socket 8: Asus P65up5; 1gb ram; 2x 200/1m pentium pros; Voodoo 1 + matrox for 2d
#4 Slot 1: Asus P2B-DS; still in planning stages. looking for processors. voodoo2 sli
#5 Slot 2: Asus XG-DLS; FINALLY found the motherboard 2 weeks ago. probably will have a voodoo 3, 2gb ram 900mhz 2mb xeons
#6 Socket 370: Dual 1.4 tualatins; 6gb ram. Used as a server until I sold it and replaced it with #8
#7 Socket 478: Dual amd 2800+'s; 2gb ddr-3200; Voodoo 5 5500. I spend MANY hours playing quake 3 on this monster.
#8 socket 604: Dual 3.8ghz irwindale xeons; 16gb ram its my server.

as you can see I have almost all the bases covered and almost all are dual socket.

Quad pentium pro's exist but are branded boxes and SUCK. I used to have a compaq one and the setup was horrid.
quad p3's exist in slot 2 xeon variety, but again are branded boxes of suck. none have agp. my dual slot 2 has agp 2x.

Now, I do have a pair of rare socket 8 -> slot one converters but I havent found a motherboard that will take them. So far they only work on 440FX chipset boards and not the 440BX that has agp.

On a side note; if you have a 468 board that meets the following requirements I want to buy it:

at least 1 Vlb slot
4 pci slots
capable of 1mb l2 cache
capable of 156mb ram (prefer edo)

I watched in horror as a shuttle hot-433 slipped through my fingers on ebay as I forgot when it ended and I missed the auction.

And for the record, pentium pro processors are my favorite.

 

[Old Thrashbarg]

Now, I do have a pair of rare socket 8 -> slot one converters but I havent found a motherboard that will take them. So far they only work on 440FX chipset boards and not the 440BX that has agp.

Try looking at 440LX boards. I have an old PII workstation with the LX chipset, and the manual specifically states support for Socket8->Slot1 adapters, so I'd expect there are other boards that can do it too.