0062 A Pentium Overdrive exposed issues with my 486 motherboard
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- Опубликовано: 30 май 2023
- On today's SMMC, we have a Pentium Overdrive CPU (For the 486) that when tested revealed some issues with my 486 test bench! We also have a Floptical drive that I test out.
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Hi Adrian, when you looked the board up on the website, the image showed it with an AMI BIOS, maybe changing the BIOS might give you more control over the cache.
@Adrian: After recently restoring my own DX2-66 PC, I suspected your speed600 results were quite low, so I ran both it and cache check on my 486 to find out. My PC is a 5V AMD DX-2 66 with 256kb of L2 cache. The board is a PCChips M601 - also a VLB board. In cache check, my setup scores 16 microseconds from 1-8, and 26 microseconds from 16-256. In speed600, the CPU score is 317.11 Mhz and FPU is 488.00 Mhz. So from what I can tell, even your 486 DX-2 66 should be performing much better than it is.
As someone else mentioned, they made a 63Mhz PODP5. I had one and OCed it to 83 with no problem. Got it at a garage sale in the mid 90s for $1 - best upgrade of my life!
I remember the early days of SATA drives. Hybrid power was VERY common. Not many people had SATA power PSU's. so they did molex for a while to help bridge the gap. I remember getting all excited when I bought my first SATA only drive that no longer had molex.
You're right about the overdrive having some kind of protection if the fan isn't running. I had a similar situation happen to me with a Pentium overdrive, where processor was running super slow for no apparent reason. I pulled the cover off the computer and noticed that the fan was not turning. Once the fan was reconnected and spinning properly all was back to normal.
Pentium technically had separate Instruction and Data caches within it's L1 cache, rather than the Unified L1 that i486 ran... This might require a later BIOS or chipset that specifically recognises the difference.
I have a 486 motherboard with the Contaq 82C495A chipset (a Lion Computers Local ISA 486 that also has a "Made in USA" sticker on it), and I took a look at the Pentium Overdrive during a livestream. Both L1 and L2 caches were functioning with the Intel processors I tried (I went back and verified what cache check told me), however, my board only works in write through mode even though this is supposedly Contaq's write-back cache chipset.
I love your channel, I have never been into computer repair or building but these are very interesting, I could watch all day.
You guys remember the over drive ready boards with the extra Big Blue Socket with white letters on it? :)
I'm betting this is more of a chipset issue. Chipset incompatibilities combined with price helped kill POD sales. One of AMDs 5x86 chips just made more sense as an upgrade. You could hunt down a regular AMI/Award Bios for the chipset (ideally one post POD release) and see if that helps.
Adrian, MR BIOS was usually an aftermarket bios people used for compatibility issues. I'd bet anything the MR BIOS on that board is not the appropriate build for that exact board, even if it's "close enough" for the chipset. As another commenter mentioned, using an official AMI BIOS might solve your cache issue.
I have checked with Landmark System Speed 6.00 (speed600) and my DX2-66 result is:
The drive with both SATA and Molex power connectors were made in the transitional period between IDE drives and SATA drives. They were for people who upgraded their systems with SATA ports, but still had old PSUs with only Molex connectors. Also, do not connect both the SATA and Molex power connectors at the same time.
I miss the days when you could just pop in a new chip, and get 2x 3x or 4x (or more!) performance from the original chip, same motherboard. It seemed like magic at the time.
Yet another awesome video!!!
The spikes on the inside of the telecom connector are used for clipping onto single conductor wire through the jacket. Might come in handy somewhere for checking. Voltages where the terminations are difficult to access.
There could be a number of factors at play when benchmarking the performance. The motherboard BIOS has a problem correctly recognising the POD-83 (possibly around L1 cache) causing the benchmarking software to give false results, or the BIOS is correct and the software is at fault. I noticed Speed Mark 6.0 was copyrighted 1993, the POD-83 was released two years later. Perhaps it's mis-reading the CPU (note in the screenshot at
That big sheet of foam may be handy for sorting all those loose ICs… now all we need to do is start scaring up a supply of IC tubes so they can be properly stored. The 4547 is a higher current version of the trusty 74LS47.
Adrian - you were right about the Dot's pretzels - picked up a pack of the honey mustard and they are great!! :)
This reminds me of the OptiFloppy and the Imation Superdisk being originally developed by Commodore for the Amiga. I can't remember who they partnered with but this also shares technology with the Iomega Zip disk. Of course by then they didn't need the optical track on the top of the disk. To answer your question though, yes that drive will in fact read and write regular 3-1/4" disks