486 Interposers and Upgrades

100 MHz Type 3 Upgrade (mod by Peter, article by Tam Pham)
Type 3 5x86 @ 150 MHz vs Type 4 P60 Benchmarks (by Jim Shorney)

AMD 5x86-P75 with an Interposer
Evergreen 586
OS Issues

AMD 5x86-P75 with an Interposer

From Jim Shorney:
   Well, this is another one of those subjects that has been discussed to death here, but here's the scoop: I replaced the 486DX-50 with an AMD 5x86-P75ADW (some folks say you need the ADZ because of the higher thermal rating, but I had no troubles withe the ADW).

   I used a PowerLeap interposer to get the voltage right, with a standard fan/heatsink, and set the CPU to x3 mode to get 150 MHz. It happily ran OS/2 Warp 4.0 and NT Workstation 4.0 for many months (until last night when I installed the type 4), and was rock stable. Not bad for a cheap, screwy CPU... :)

Evergreen 586

Successful upgrade by Bradley Parker

CPU:
Evergreen Technologies, Inc
Model G 1 REV 1 MADE IN USA
AMD Am5x86 P75 (soldered QFP package)
(no other model numbers on chip, lot #1375)

Jumper Settings (x=closed)

Status	Label	Function
	WB	Write-Back Cache
X	WT	Write-Through Cache
X	3X	3X Clock Multiplier
	4X	4X Clock Multiplier
	OvrDrv	Overdrive Socket
X	Nrml	Normal CPU Socket

Write-back causes weird behavior. 4x won't run.

More info about the Evergreen upgrade HERE.

OS Issues

Unable to install Win98 because the processor is not at least 66MHz. NT4.0 fails on install also (unable to find files needed for networking).

From Jim Shorney:
   Use "setup /nm" for W98. You may have SCSI problems w/98. I was never able to get it to run w/o DOS mode using the Evergreen. Put the stock 50Mhz back in and it was fine, so I am currently running NT4.0 SP5 on mine. No problems with NT.

> I got it to run just fine with the Type 3 DX-50. Never understood why others had so many problems with it.

From Peter:
   That Type 3 DX50 (-xMx models) is the only exception I found so far. All my other machines (Mod. 90 / T2 DX2-25/50, 8595-AKD /T1 DX-33, 9577-1NA / DX2-33/66) fell flat on the face and into 16-bit mode. Only the "Lacuna" with the Fast SCSI-2 Future-Domain derived controller and the 9595-AMT with T3 DX50 worked.

> Is this upgrade possible with the Kingston Turbo Chip but not the Evergreen?

From Jim Shorney:
   Known to work better with the Evergreen. Cache policy problems with the Kingston. Can't see more than 32 MB, floppy no workie etc... Same problems with write back cache on the Evergreen. Evergreen has the jumper which fixes those.