386DX-40, ImageDisk, & 387 socket

So I have this board with a 386DX-40 that I want to use with the ImageDisk software which requires 486 or better.. The 386DX-40 is pretty zippy due to it's 40Mhz bus, so I think it's in the ballpark as "fast enough" for Imagedisk. Is that a good assumption?

To give the system more omph, I want to add a 387 math coprocessor in case ImageDisk does lots of math. I've seen 387 sockets before, but this one is the first I've seen that has a dip socket next to it for a crystal, and a jumper that says "1-2 use 386 clock for 387, 2-3 use 387 crystal for 387". Which is awesome, as I'm having no luck finding a 387 40Mhz. So will a math coprocessor help ImageDisk? (I'll get a 387 anyways, since that socket is just sitting there unused...)

Ha, just did a quick search on ebay and ta-da, find some 80387 40Mhz on ebay n the package I need. So is $36 shipped a decent price, or can I find a 33Mhz version around for much cheaper?

I think you are in the wrong part of this forum..

You are posted you topic in:

Older PC architectures from IBM and others - 8088 to 286 only!

Get a 40mhz one to match your processor speed or you will need to find a crystal osscilator to change the frequency so it will work (socket next to the FPU).

Robin4 said:

I think you are in the wrong part of this forum..

You are posted you topic in:

Older PC architectures from IBM and others - 8088 to 286 only!

Click to expand...

D'oh! I saw the "Later PCs" forum, but must have clicked the "PC's and Clones" instead! Can someone move it to "Later PCs"?

I use ImageDisk with a 386/20. Plenty fast enough. An 8MHz 80286 would probably be fast enough.

The ImageDisk source code uses no floating point as far as I can see so the 387 will provide no benefit.

Chuck(G) said:

I use ImageDisk with a 386/20. Plenty fast enough. An 8MHz 80286 would probably be fast enough.

Click to expand...

Are we all talking about Dave Dunfield's ImageDisk? I also use it on a slow 386 and never a problem; where did you (OP) get the idea that it needs a 486+ ?

MikeS said:

Are we all talking about Dave Dunfield's ImageDisk? I also use it on a slow 386 and never a problem; where did you (OP) get the idea that it needs a 486+ ?

Click to expand...

I downloaded Dave Dunfield's ImageDisk 1.17 and in the imd.txt file, the 1.2 System Requirements section says "Although ImageDisk will run on a 4.77Mhz PC/XT type machine, some of the analysis functions are real-time intensive and best results will be obtained with a 486 class machine or better."

krebizfan said:

The ImageDisk source code uses no floating point as far as I can see so the 387 will provide no benefit.

Click to expand...

Ah good idea to check the source - I also did the same to doublecheck, grep'd the source code for double or float, and neither showed up. So it's all integer math afaik too.

Soupwizard said:

I downloaded Dave Dunfield's ImageDisk 1.17 and in the imd.txt file, the 1.2 System Requirements section says "Although ImageDisk will run on a 4.77Mhz PC/XT type machine, some of the analysis functions are real-time intensive and best results will be obtained with a 486 class machine or better."

Click to expand...

Right you are, thanks; I don't think a 486 is required though, and certainly not for normal imaging work.

(redacted)