486 Pentium Overdrive - Third Time Is The Charm

When I got back into retro computing, I had a number of computers I wanted to recreate that I had in the past. One of those was a 486 computer upgraded to a Pentium Overdrive CPU. I found a 486 computer on Craigslist for only $50. I purchased it along with the $20 Pentium 133 system I wrote about a few posts ago. Unfortunately, the motherboard had a standard 168 pin 486 CPU socket. I forgot a Pentium Overdrive CPU requires 238 pin Socket 2 or 237 pin Socket 3 motherboard and so strike one. I ended up selling that motherboard to a friend for his own 486 build. I next purchased a 486 Socket 2 motherboard from eBay. Although the Pentium Overdrive worked in this board, it performed well below what it was supposed to. I later found out the motherboard came out of an arcade machine and there was no documentation to be found anywhere on the jumper settings for the CPU and so strike two. I ended up using that motherboard in 486DX2/80 build and it is working fine for that. Finally, I did my homework and found another motherboard on eBay that I knew would work and I had documentation for. I got a Lucky Star LS-486E revision C1 Socket 3 motherboard. This one I am glad to say fully supports my Pentium Overdrive CPU and is working great!

What is a 486 Pentium Overdrive CPU? It is an upgrade from Intel to retro fit a Pentium CPU into a 486 socket. There were two versions the PODP5V63 for 25MHz FSB 486 systems and runs at 63MHz and the PODP5V83 for 33Mhz FSB 486 systems and runs at 83Mhz. This is the one I have. Having a Pentium core in 486 package means there are some bottlenecks. A full Pentium will have a full 64-bit data path and 66MHz FSB. The Pentium Overdrive is on a 33MHz FSB and 32-bit data path. Intel did increase the L1 cache to 32K (16K code & 16K data) to help offset this. It has the branch prediction, dual instruction pipeline and faster FPU of a full Pentium. There are other upgrades for 486 systems, but this is the one I had years ago. My system has the follow specs:

    Pentium Overdrive 83MHz CPU

    72-pin 32MB FPM SIMM

    ViewTop ET6000 4MB PCI video card

    Sound Blaster 16 CT4170 ISA sound card

    3Com Etherlink III ISA network card

    8GB CompactFlash card with CompactFlash adapter

    1.44MB 3.5” floppy drive

    32x CD-ROM drive

    Windows 95 OSR2.5

The biggest advantage of the Pentium Overdrive over other 486 upgrades is that it will run software optimized for the Pentium CPU and 3D games like Quake much faster. There were not a lot of these CPUs sold and makes them rarer. You will generally see only a few listed-on eBay at any one time. They easily fetch over $125. Luckily, I got my much cheaper than that. What are my impressions now that I have this computer system put together? From a nostalgia perspective it was everything I had hoped. From a practical perspective, a Pentium system is much cheaper to put together and will perform much better. I opted for the memories and I cannot put a price on

Pentium Overdrive 83Mhz running on Windows 95 OSR2.5
Pentium Overdrive 83MHz top view
Pentium Overdrive 83MHz bottom view
Pentium Overdrive 83MHz heatsink and fan removed
Pentium Overdrive 83Mhz box cover front
Pentium Overdrive 83Mhz box cover bottom







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