The background...
As a child I remember being taken to my local computer shop where on the shelf they had a big collection of processors on display, some of which were the Pentium Pro models. The prices ranged up to several thousand pounds per CPU. I was amazed some of them could be so expensive and wondered what they offered for the money compared to the standard pentiums at only a few hundred pounds.
Recently I saw a Pentium Pro motherboard for sale and as it's getting quite difficult to find the bits to build one of these nowadays I decided that now (only 18 years late!) would be a good time to start.
The build:
Motherboard:
Tyan S1662 D - Dual Socket 8 'BabyAT'
If you're going to have a Pentium Pro it makes sense to double up! Dual boards are fairly rare to find and many are designed for specific workstations or servers which use proprietary connectors, boards or power supplies. This board is a standard BabyAT board which means few or no incompatibly issues. This board retailed for £485 in 1997.
Here are the CPU sockets. They have 387 pins each and are quite strange in that half the socket is laid out in PGA and the other half in SPGA. The photo probably doesn't show just how big these sockets are. It's very dusty but as I've run out of air duster at the moment it's going to have to stay like that until I can get some more.
This board takes 72pin SIMM memory. There are 8 slots in total and the board can take up to 1GB of ram using 8x 128MB SIMMS. There weren't many boards that could take this amount of memory in 1997.
Back in 1997 16MB was considered a decent amount of memory and 32MB was considered to be future proof. To be able to use so much memory must have seemed insane! Also chipsets of this era would generally only be able to cache a smallish amount of memory (the l2 cache was on the motherboard.) This meant maxing out the memory of your motherboard on most systems would actually slow them down dramatically.
With the progression from 486 to Pentium systems PCI slots were begining to take over from ISA slots. The board has 3 ISA slots and 4 PCI slots. The PCI slots are massively faster offering 66MB/s bandwidth compared to the ISA slots measly ~8MB/s.
Here is the keyboard connector which is the rather large DIN type. It is the only I/O port on the board. The rest need to be made up using backplates connected to header ports or PCI/ISA cards.
You can also see the power connector for the board. AT motherboards used 2 8pin cables which connected side by side give 16 pins for the power. You can also see the header for the ps/2 port for the mouse.
Next to each CPU socket is a VRM slot. Pentium Pro CPUs required VRMs to be plugged into the motherboard to deal the power draw required.
Here are the VRMs. They are both Corsair but slightly different model numbers. I think one might be rated for a higher power but I can't find any details.
Here is the memory I am using. 4x 64MB Edo SIMMS for a total of 256MB. It would have cost £245 for each 64MB SIMM back in 1997!! With so much RAM the 'Quick' memory test at POST takes over 2 minutes to complete.
They are 60ns modules rated for running at 66mhz and should give close to 100MB/s of memory bandwidth.
I fitted a new battery. The board doesn't take a button type battery but takes a 19 pin rectangle chip with the battery inside. It also acts as the real time clock for the computer.
Here is where it fits on the board.
Now the interesting bit, the processors!
The Pentium Pro CPU was well ahead of it's time on release. It featured on package L2 cache. This was at a time when in other processors the L2 cache was found on the motherboard rather than the CPU. The cache was difficult and expensive for Intel to produce and the processors were priced accordingly. Also the CPU could read the main memory and cache at the same time. A pentium or equivalent could only do one or the other.
The on package cache gave a huge advantage in multiprocessor computers. Where as two CPUs sharing one cache on a motherboard would give a performance hit, Pentium Pro has the cache on each CPU.
The processor did have a couple of downsides though. It was highly optimized for 32bit applications and was slower than a Pentium MMX in 16 bit applications. Windows 9x was mostly 16bit, so to get full performance you needed to be using Windows NT4 and 32bit applications.
The other downside was that the Pentium Pro has no MMX, meaning slower performance in applications that support it and the inability to run programs coded to require MMX.
However the design of the P6 microarchitecture carried over all the way to the Tualatin pentium III and (wikipedia tells me) it is what evolved into the Core 2 CPUs.
Intel initally released models ranging from 150mhz-200mhz with 256KB cache. All the intial models were designed for high end workstations except one. This was an ultra high end chip running at 166mhz with double the cache of the workstation models.
The retail price of the 200mhz workstation model was around £1200 whereas the 166mhz 512k cache server version would set you back over £1500 per CPU!
With this in mind the 166mhz models were the ones I wanted. Here is what they look like.
Geeky fact. These CPUs contain the most gold per CPU of any, as far as I know.
I also got a 'brand new' sealed 180mhz chip in the original box. It has a case sticker inside I really want to get out but since it's still sealed I think I'm going to leave it as it is, as a very geeky souvenir.
Most CPUs of this era had very small heatsinks, and with the Pentium MMX models you often got a small fan. The Pro model required more cooling, a lot more. A standard Penitum 166mhz model had a TDP of 14.5w whereas a PPro 166 512 cache made around 2.5x the heat with a TDP of 35w.
I managed to get some new old stock heatsinks to keep them cool.
I got hold of a AT case and set about installing the board. This was much more difficult than I expected as the board is almost exactly the size of the space in the case. I had to remove the heatsinks and VRMs to be able to squeeze it in at an angle.
Next was time to set the jumpers. This was fairly easy as Tyan still has the manual for the board on their website. It was just a case of setting the jumpers to 2.5x 66 for 166mhz.
Then the moment of truth... Whenever I build a new PC I always wonder if it will fire up first time, but this one using nearly 20 year old components... I had no idea if it would work or if it would blow up.
It works!!
A quick install of Windows NT4 to test everything was working...
and then it was time to err...... upgrade !
The reason being, in 1997 Intel released the ultimate version of the Pentium Pro. A 200mhz model with 1MB on package L2 cache.
The 1MB version required a compatible motherboard, BIOS update and uprated cooling.
Tyan had a bios update program you could download from their website. Unfortunately it didn't work however I managed to get hold of a suitable version of the award flash program which I ran from a floppy disk.
It didn't give any indication as to if the flash was successful or not but I left the computer on for quite a while to be safe then power cycled... Luckily the bios updated successfully.
This allowed support for the 1MB 200mhz chips and also added Ultra DMA hard disk support which once I get a better hard drive installed should massively boost performance. On the original bios the board only supported DMA2 which at 16.7MB/s was pretty slow. I am currently waiting for a new super fast (haha) drive to arrive for it.
I also needed better cooling as the heatsinks I got were fairly small. Socket 8 Heatsinks are difficult to find as they are only used on PPro CPUs. I managed to get some comparatively huge heatsinks designed for semi passive use then added the high power fans from the other heatsinks.
These heatsinks are taller than the standard heatsink and fan put together.
So the processors themselves...
Everyhing about these chips were insane compared to the Pentium MMX. Here's a quick comparison:
Pentium 200mhz MMX VS Pentium Pro 200mhz 1MB
Die size 141 mm^2 VS Die size 680 mm^2
Transistors 4.5 million VS Transistors 67.5 million
TDP 15.7w VS TDP 47w
UK Retail ~ £500 VS UK Retail ~ £2400
Because of the huge cache it had 15x as many transistors as the Pentium MMX and including that cache the die size was just under 5x the size of the Pentium MMX.
The cache was so large physically they had to redesign the housing of the processor and it ended up being made out of black plastic instead of ceramic like the lower spec chips.
For a size comparison of just how big these chips are, here's a picutre of a 2005 mobile Athlon on the PPro 1MB.
Ready for their new home haha
Fitted!
All working! Boot screen showing 2x 1024KB cache.
I'd read online that the Pentium Pro runs very hot and while using the 166mhz 512k versions I was thinking that it was a little bit of an exaggeration. They were hot but not worse than I expected.
The 1MB versions though... From totally cold even with the fan at full speed it takes literally seconds before you can no longer comfortably touch the heatsinks. Because I'm using a standard desktop case there are no fans for air moment and even with the case side off (definately can't put it on!) it's like a mini oven.
I did have a go at undervolting the processors (which takes 10 jumpers!). There is no display in the bios to tell you the voltage so I used a watt meter on the plug socket instead. Unfortunately the VRMs set a min voltage. You can go over it but not under it.
So that's roughly where I'm up to so far. I used the internet achieve to look up prices and total cost so far in 1997 would be approximately £7048 which allowing for inflation would be around £11,820 !!!
It's not too bad though compared to pre built computers at that time. When IBM and ICL launched their first Pentium Pro servers they started at £15,000 for a single 166mhz 512k processor system and were over £30,000 for a dual 166mhz 512k system.
More geeky facts
A few super high end PPro systems were designed, one being the ICL J600 superserver which had 4x PPro 166 512k CPUs, 2GB ram and 240GB of storage, priced at OVER £100,000 (!!!!!!) the other being a 6 way Ppro 200 system however that was much less expensive as it was a few years later.
Oh and a certain supercomputer used these processors too, 9298 of them.
If you've got to the bottom of this post then congratulations, it sure was a long one. Now I've got it working I've got no idea what to do with it !
Apologies if any facts are wrong. Please feel free to correct me
As a child I remember being taken to my local computer shop where on the shelf they had a big collection of processors on display, some of which were the Pentium Pro models. The prices ranged up to several thousand pounds per CPU. I was amazed some of them could be so expensive and wondered what they offered for the money compared to the standard pentiums at only a few hundred pounds.
Recently I saw a Pentium Pro motherboard for sale and as it's getting quite difficult to find the bits to build one of these nowadays I decided that now (only 18 years late!) would be a good time to start.
The build:
Motherboard:
Tyan S1662 D - Dual Socket 8 'BabyAT'
If you're going to have a Pentium Pro it makes sense to double up! Dual boards are fairly rare to find and many are designed for specific workstations or servers which use proprietary connectors, boards or power supplies. This board is a standard BabyAT board which means few or no incompatibly issues. This board retailed for £485 in 1997.
Here are the CPU sockets. They have 387 pins each and are quite strange in that half the socket is laid out in PGA and the other half in SPGA. The photo probably doesn't show just how big these sockets are. It's very dusty but as I've run out of air duster at the moment it's going to have to stay like that until I can get some more.
This board takes 72pin SIMM memory. There are 8 slots in total and the board can take up to 1GB of ram using 8x 128MB SIMMS. There weren't many boards that could take this amount of memory in 1997.
Back in 1997 16MB was considered a decent amount of memory and 32MB was considered to be future proof. To be able to use so much memory must have seemed insane! Also chipsets of this era would generally only be able to cache a smallish amount of memory (the l2 cache was on the motherboard.) This meant maxing out the memory of your motherboard on most systems would actually slow them down dramatically.
With the progression from 486 to Pentium systems PCI slots were begining to take over from ISA slots. The board has 3 ISA slots and 4 PCI slots. The PCI slots are massively faster offering 66MB/s bandwidth compared to the ISA slots measly ~8MB/s.
Here is the keyboard connector which is the rather large DIN type. It is the only I/O port on the board. The rest need to be made up using backplates connected to header ports or PCI/ISA cards.
You can also see the power connector for the board. AT motherboards used 2 8pin cables which connected side by side give 16 pins for the power. You can also see the header for the ps/2 port for the mouse.
Next to each CPU socket is a VRM slot. Pentium Pro CPUs required VRMs to be plugged into the motherboard to deal the power draw required.
Here are the VRMs. They are both Corsair but slightly different model numbers. I think one might be rated for a higher power but I can't find any details.
Here is the memory I am using. 4x 64MB Edo SIMMS for a total of 256MB. It would have cost £245 for each 64MB SIMM back in 1997!! With so much RAM the 'Quick' memory test at POST takes over 2 minutes to complete.
They are 60ns modules rated for running at 66mhz and should give close to 100MB/s of memory bandwidth.
I fitted a new battery. The board doesn't take a button type battery but takes a 19 pin rectangle chip with the battery inside. It also acts as the real time clock for the computer.
Here is where it fits on the board.
Now the interesting bit, the processors!
The Pentium Pro CPU was well ahead of it's time on release. It featured on package L2 cache. This was at a time when in other processors the L2 cache was found on the motherboard rather than the CPU. The cache was difficult and expensive for Intel to produce and the processors were priced accordingly. Also the CPU could read the main memory and cache at the same time. A pentium or equivalent could only do one or the other.
The on package cache gave a huge advantage in multiprocessor computers. Where as two CPUs sharing one cache on a motherboard would give a performance hit, Pentium Pro has the cache on each CPU.
The processor did have a couple of downsides though. It was highly optimized for 32bit applications and was slower than a Pentium MMX in 16 bit applications. Windows 9x was mostly 16bit, so to get full performance you needed to be using Windows NT4 and 32bit applications.
The other downside was that the Pentium Pro has no MMX, meaning slower performance in applications that support it and the inability to run programs coded to require MMX.
However the design of the P6 microarchitecture carried over all the way to the Tualatin pentium III and (wikipedia tells me) it is what evolved into the Core 2 CPUs.
Intel initally released models ranging from 150mhz-200mhz with 256KB cache. All the intial models were designed for high end workstations except one. This was an ultra high end chip running at 166mhz with double the cache of the workstation models.
The retail price of the 200mhz workstation model was around £1200 whereas the 166mhz 512k cache server version would set you back over £1500 per CPU!
With this in mind the 166mhz models were the ones I wanted. Here is what they look like.
Geeky fact. These CPUs contain the most gold per CPU of any, as far as I know.
I also got a 'brand new' sealed 180mhz chip in the original box. It has a case sticker inside I really want to get out but since it's still sealed I think I'm going to leave it as it is, as a very geeky souvenir.
Most CPUs of this era had very small heatsinks, and with the Pentium MMX models you often got a small fan. The Pro model required more cooling, a lot more. A standard Penitum 166mhz model had a TDP of 14.5w whereas a PPro 166 512 cache made around 2.5x the heat with a TDP of 35w.
I managed to get some new old stock heatsinks to keep them cool.
I got hold of a AT case and set about installing the board. This was much more difficult than I expected as the board is almost exactly the size of the space in the case. I had to remove the heatsinks and VRMs to be able to squeeze it in at an angle.
Next was time to set the jumpers. This was fairly easy as Tyan still has the manual for the board on their website. It was just a case of setting the jumpers to 2.5x 66 for 166mhz.
Then the moment of truth... Whenever I build a new PC I always wonder if it will fire up first time, but this one using nearly 20 year old components... I had no idea if it would work or if it would blow up.
It works!!
A quick install of Windows NT4 to test everything was working...
and then it was time to err...... upgrade !
The reason being, in 1997 Intel released the ultimate version of the Pentium Pro. A 200mhz model with 1MB on package L2 cache.
The 1MB version required a compatible motherboard, BIOS update and uprated cooling.
Tyan had a bios update program you could download from their website. Unfortunately it didn't work however I managed to get hold of a suitable version of the award flash program which I ran from a floppy disk.
It didn't give any indication as to if the flash was successful or not but I left the computer on for quite a while to be safe then power cycled... Luckily the bios updated successfully.
This allowed support for the 1MB 200mhz chips and also added Ultra DMA hard disk support which once I get a better hard drive installed should massively boost performance. On the original bios the board only supported DMA2 which at 16.7MB/s was pretty slow. I am currently waiting for a new super fast (haha) drive to arrive for it.
I also needed better cooling as the heatsinks I got were fairly small. Socket 8 Heatsinks are difficult to find as they are only used on PPro CPUs. I managed to get some comparatively huge heatsinks designed for semi passive use then added the high power fans from the other heatsinks.
These heatsinks are taller than the standard heatsink and fan put together.
So the processors themselves...
Everyhing about these chips were insane compared to the Pentium MMX. Here's a quick comparison:
Pentium 200mhz MMX VS Pentium Pro 200mhz 1MB
Die size 141 mm^2 VS Die size 680 mm^2
Transistors 4.5 million VS Transistors 67.5 million
TDP 15.7w VS TDP 47w
UK Retail ~ £500 VS UK Retail ~ £2400
Because of the huge cache it had 15x as many transistors as the Pentium MMX and including that cache the die size was just under 5x the size of the Pentium MMX.
The cache was so large physically they had to redesign the housing of the processor and it ended up being made out of black plastic instead of ceramic like the lower spec chips.
For a size comparison of just how big these chips are, here's a picutre of a 2005 mobile Athlon on the PPro 1MB.
Ready for their new home haha
Fitted!
All working! Boot screen showing 2x 1024KB cache.
I'd read online that the Pentium Pro runs very hot and while using the 166mhz 512k versions I was thinking that it was a little bit of an exaggeration. They were hot but not worse than I expected.
The 1MB versions though... From totally cold even with the fan at full speed it takes literally seconds before you can no longer comfortably touch the heatsinks. Because I'm using a standard desktop case there are no fans for air moment and even with the case side off (definately can't put it on!) it's like a mini oven.
I did have a go at undervolting the processors (which takes 10 jumpers!). There is no display in the bios to tell you the voltage so I used a watt meter on the plug socket instead. Unfortunately the VRMs set a min voltage. You can go over it but not under it.
So that's roughly where I'm up to so far. I used the internet achieve to look up prices and total cost so far in 1997 would be approximately £7048 which allowing for inflation would be around £11,820 !!!
It's not too bad though compared to pre built computers at that time. When IBM and ICL launched their first Pentium Pro servers they started at £15,000 for a single 166mhz 512k processor system and were over £30,000 for a dual 166mhz 512k system.
More geeky facts
A few super high end PPro systems were designed, one being the ICL J600 superserver which had 4x PPro 166 512k CPUs, 2GB ram and 240GB of storage, priced at OVER £100,000 (!!!!!!) the other being a 6 way Ppro 200 system however that was much less expensive as it was a few years later.
Oh and a certain supercomputer used these processors too, 9298 of them.
If you've got to the bottom of this post then congratulations, it sure was a long one. Now I've got it working I've got no idea what to do with it !
Apologies if any facts are wrong. Please feel free to correct me
