CPU Trivia
63 vs. 83 MHz POD
Difference Btween Socket 4, 5, and 7 (From PowerLeap)
Metal Capped Chips
Evergreen 133 Interposer
496 vs. 497 Cache controller
487 Upgrade
ODP in ODPR Socket?

Dr. Dobb's Microprocessor Resources (takes you from my site)
On-line Intel documentation
   MMX Specification 
   Pentium (and Pentium MMX) Documentation  496/497/498 Cache controller, too!
   Intel486 Documentation
   Intel386 Documentation
   80186 Documentation Used on SCSI w/cache, Fast/Wide....
   Application Notes 

Chiplist (CPU and NPX list)



83MHz POD vs. 63MHz POD
>  How far can the 83MHz POD be pushed? What is the highest practical clock speed that won't make one spin so fast, it churns itself into butter?

POD Boy
   It runs fine at 40MHZ. ( 2.5 X 40 = 100MHZ ). Benchmarks are VERY impressive at this level also. If you figure out a way to get the Lacuna to 40MHZ, please let me know.

Jim Shorney
   I dunno about the 83, but I'm running a 63 at 83.  In a Lacuna.  With no interposer.  Rock stable, and barely gets lukewarm.

From Peter
Most likely the two chips are made from identical cores ... 
   The 83 is intended to run in 33MHz systems with internal 2.5x clocking. The 63 is to be used in 25MHz systems also with 2.5x clocking ... but the chips are most likely made from one wafer and only labelled differently. It were a waste and inefficient to make two (technically identical) "low end" chips / upgrades with two different masking- and selection-processes.
   The good old Intel marketing gag to sell "higher rated" processors at higher prices.
   I found the PODP5V63 already stable enough to run at 33MHz when I upgraded customers machines back in '94 (PS/VP-2) and we temporarily ran out of 83-versions. I think they have been used with the 63-types until the end (about 2 or 3 years).



Metal Capped Chips
>That complex run DX4 chips fine.  At any rate with any CPUs I'm bit nervous about those aluminum ESD cans running HOT than I'm used to on other "warm ~ hot" chipsets in peecees.  Know of vendor selling doublesided thermal conductive stickers?  I have lot of heatsinks collected when fans failed.

From Peter 
   Err ... no need to worry. These ESD-capped chips are pretty rigid. They are in fact ceramic under this aluminium shield and have been designed for temperatures *far* over what's normal in "generica" PCs. I think they are spec'd for 75°C and above - that's so hot you cannot touch them with bare fingers. They have been (originally) designed for the use in mainframes and minis. :-)


Evergreen Interposer

OD  Use top pins if only one socket on board - even if marked “OverDrive Ready”. If installed in an OverDrive socket, use bottom two pins.
CB Solder pads for 4 pin header. Where present, The top two pins are labled "WT" and the bottom two "CB" - Write Through and Cache Back
Clock Jumper The 4X/2X selects quadrupling mode, 3X selects tripling mode.
BLK/RED I think this is a socket to supply 5v to a CPU fan.
 
 
 
 



496 vs. 497 Cache Controller

From Dr. Jim Shorney
   Overdrive processors are not compatible with the '496 cache controller on the P60/66 complexes.  However...
      I swapped out the '496 cache controller on mine for a borrowed '497 (well heatsinked)  and was able to boot DOS with a POD 133 on my P60 (overclocked to 66).  It wasn't entirely stable, and would not boot OS/2 Warp 4.0 or NT 4.0.  The Powerleap PL54C interposer was still dead in this configuration.  There may yet be hope, I haven't tried the Powerleap with anything other than an Intel 166 yet, and I may also downclock the complex back to 60 MHz and see what happens.  There may yet be hope...
      The '497 reportedly has a 3.3v core, but it seemed to run stable and reliable for several hours with the stock P60 CPU in my system in place of the 5v '496.

   I briefly looked over the docs this afternoon (712 pages, wow...). Seems the '497 is still a 5v part, it is the I/O buffers that connect to the CPU that are 3.3v.  This probably explains in part why the chip doesn't self-destruct in the '496 socket.  It also seems to invalidate the need for an interposer, since the P60/66 I/O is 5v anyway and the buffers would have to run at 5v to interface at all with the CPU.  This brings up the question of noise immunity, though - will circuits designed to run at 3.3v logic levels be more or less sensitive to noise or poor signal quality when run at 5v?  Inquiring minds want to know. 

From Tony Ingenoso
   I suspect noise is going to be less of a problem at higher voltages Jim.  In theory, the voltage range for correct operation would be wider(particularly for CMOS).  The only reason I ever saw (other than laptop applications) for the drive to lower voltages was to  limit heat as the gate counts and frequencies went up.
   CMOS parts like high voltages -- you can crank clock speeds faster with higher voltages(the standard overclockers trick).  Discrete type CMOS parts can often be run as high as 20V and work fine.  The downside is that its power characteristics start approaching those of TTL at the higher speeds (and heat goes up).  If the only nominally 3.3V sections of the cache controller are the line drivers/buffers, there's probably not going to be enough stuff getting overvoltaged to make any significant difference in the power draw.



486SX Upgrade?
>Can I upgrade the 9577 to 586 using the Kingston TurboChip using the spare (overdrive ?) cpu socket on the board. 

 Only if you got one of the older Kingston Turbochips that have a 486/487 jumper at the underside. The socket in the -0UA is an "upgrade socket" only. The 486SX-33 is soldered on the planar and is disabled when using a 487SX or 486SX Overdrive - not when using a 486DX, which lacks the "disable present cpu" pin.

ODP (487) in ODPR (486) Socket
From Jim Shorney
>I drilled a small hole in a 168-pin 486 socket at the 169th pin position so I could plug an ODP in.  IIRC, it was a type 1 non-SOD that I did that to.  The extra pin is the SX disable pin.  I've also used a 487 on a do-every-CPU-made clone board.

From Peter
 Okay - that's using the -OPD in an "-OPDR place". But what if you got an -OPDR and needed a "487SX-style" -OPD ? I would guess that it should to to tie the 169th pin to GND with a small piece of wire (and a resistor of 1 - 4.7 K probably to avoid potential damage). 
   Sort of using a 486DX for a 487SX ....

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