I once had a 286 motherboard that let you install DIP or SIPP, but you couldn't use them together. This probably varies according to the manufacturer.

30 pin SIMM and SIP modules are pin compatible. If you have a motherboard requiring SIP modules but you only have SIMMs, just solder some pins on.

Anonymous Coward wrote:

I once had a 286 motherboard that let you install DIP or SIPP, but you couldn't use them together. This probably varies according to the manufacturer.

Mine 286 motherboard has the same..

Dips or Sips.. (cant use both)

And i want to know about extended memory..

Could it be usefull like on the 386 and 486 systems?

I think its only needed when running `protected` mode i guess?

Or should i upgrade the ram? and make it EMS from it?

I actually want to make it extended ram because i have also EMS memory boards laying around and want to use it for EMS..

So then i could have benefit from extended and EMS memory.

That was my first thought.

SquallStrife wrote:

30 pin SIMM and SIP modules are pin compatible. If you have a motherboard requiring SIP modules but you only have SIMMs, just solder some pins on.

Yeah i know, but takes time to solder does pins on the printed circuit board connectors.

Robin4 wrote:

SquallStrife wrote:

30 pin SIMM and SIP modules are pin compatible. If you have a motherboard requiring SIP modules but you only have SIMMs, just solder some pins on.

Yeah i know, but takes time to solder does pins on the printed circuit board connectors.

I have several megabytes in sipps (willing to trade if you need them)

I had a 286 board with sipp only slots, and instead of soldering pins on some simms, I found an alternative which is a lot easier(at least for me that I don't have so good soldering skills). I had some dead 386 boards from which I desoldered the simm slots. (Not me actually, I gave them to a friend who could do that). If you have the simm slots completely intact, then it's easy to insert their pins to the sipp holes, litteraly converting the sipp to simm slots.

Extended memory has its uses on a 286 motherboard. There are a number of games that can take advantage of it, and lets not forget Windows 3.1 requires it. From what others have said, quite a number of Windows 3.1 apps only use 286 mode anyway. Windows 3.1 is usable on a 286 so long as you have at least 4MB of RAM.

Markk wrote:

I had a 286 board with sipp only slots, and instead of soldering pins on some simms, I found an alternative which is a lot easier(at least for me that I don't have so good soldering skills). I had some dead 386 boards from which I desoldered the simm slots. (Not me actually, I gave them to a friend who could do that). If you have the simm slots completely intact, then it's easy to insert their pins to the sipp holes, litteraly converting the sipp to simm slots.

That's a good tip that should be stickied somewhere. High density SIPPS are difficult to find and in any case never reached the highest density that 30 pin SIMMs did so maxing the RAM on a board with SIPP sockets can be an exercise in frustration.

Something tells me 16MB SIPPs would be of little use on a 286 motherboard.

Anonymous Coward wrote:

Something tells me 16MB SIPPs would be of little use on a 286 motherboard.

1mb SIPPS would be, though, and they are near impossible to find anymore. 256K is usually all that's available.

I think you can only address 16MB on a 286 system.

Unknown_K wrote:

I think you can only address 16MB on a 286 system.

Yes, but 30 pin simms are 8 bits, so for a 286 you have to install them in pairs.

I didn't know 1MB SIPPs were rare. At one time I had access to an entire jar full.

Once I even had a 20MHz 286 motherboard with 1mb SIPPs.

Anonymous Coward wrote:

I didn't know 1MB SIPPs were rare. At one time I had access to an entire jar full.

Once I even had a 20MHz 286 motherboard with 1mb SIPPs.

1mb SIPPS don't come up for sale often but 256K ones are for sale every day. That's one reason why it took me so long to find a fast 286 motherboard for my Harris chip, I was specifically looking for one with 30 pin SIMM slots instead of SIPP slots because I have piles of 1mb 30 pin SIMMs but no 1mb SIPPs at all. A lot of the boards I was seeing had a combination of SIPP and RAM chip sockets on the board and I didn't feel much like having to hunt down the parts to populate them.

I feel lucky now - just bought 8 SIPP modules, 2 of them are 1 mb. the lot cost about USD 10 with shipping. I can now upgrade my 20 Mhz CHIPS mobo with a Harris 20 Mhz + Intel 87XL copro to 3.5 megs.

Is your 80287XL running at 20MHz, or does it run at 1/2 or 2/3 bus speed?

Need to test that somehow. Jumper settings are for "sync to CPU" and "sync to oscillator" but the oscillator is missing from the board. The copro runs considerably hot even idle. I am thinking about getting a heat spreader for it.

I think i solve the big problem.. I won a couple of 1MB sipps.. So i think to remove the 256K Dip from that board..
I have also installed a AMD 287 12mhz co-processor on it..

But on the question of that extended memory.. I much do i need exactly to run windows on it> is 1400MB just enough?

Other question..

Are 531000 dips the same as 511000 dips.

the 53ers are 70ns
the 51ers are 10 ns

80287XL was only ever rated by intel to run up at speeds of up to 12.5MHz....but this may have been because intel itself never made 286s faster than that (AMD and Harris did). A heatsink is probably a pretty good idea though, otherwise you should get a Cyrix or IIT FPU rated for 20MHz.