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Upgrade for 386SX such as Cyrix 486 DRX or Texas Instument Make it 486 etc
- Thread starter limboy777
- Start date
TJ_Mossman
Experienced Member
I have a TriSys Technology board which allows a 486 DX2-50 to be plugged into a 386 socket. Is that of any interest?
Hi it needs to be one that clips on top of the existing CPU. The CPU is soldered on. Do you have anything like that?
TJ_Mossman
Experienced Member
I'm afraid not, this one needs an empty socket.
Thank you for taking the time to reply. I am looking for Cyrix or Texas Instruments upgrades that clip on top of existing CPU's.
g4ugm
Veteran Member
If its a 386SX chip you have that's only a 16-bit bus and a Cyrix486DRX won't do the job. In any case the 486DRX is a plug-in replacement not a "clip on top" chip. I think the same goes for most of the other "486" conversions, they won't fit on the 386SX as its a different layout to the normal 386 chip. From what I remember the 386SX was a real dog because it had a 16-bit bus...
g4ugm
Veteran Member
ops add here:-
https://books.google.co.uk/books?id...C4Q6AEwAg#v=onepage&q=Cyrix 486 DRX 2&f=false
shows you really need a 486SRX2 but it won't really make it a 486 as it still has a 16-bit external bus and it will still run like a dog...
The 386SX was the odd chip out in the SX "named" chips. Both the 80286sx and the 80486sx are just the same chip less the maths co-processor. The 80386SX has a maths co-processor, but only a 16-bit bus, unlike its big brother the 80386 which has a 32-bit bus. To be honest I don't think a "Make It 486" on a 386sx board would offer good value for money if you are looking for a speed upgrade.
https://books.google.co.uk/books?id...C4Q6AEwAg#v=onepage&q=Cyrix 486 DRX 2&f=false
shows you really need a 486SRX2 but it won't really make it a 486 as it still has a 16-bit external bus and it will still run like a dog...
The 386SX was the odd chip out in the SX "named" chips. Both the 80286sx and the 80486sx are just the same chip less the maths co-processor. The 80386SX has a maths co-processor, but only a 16-bit bus, unlike its big brother the 80386 which has a 32-bit bus. To be honest I don't think a "Make It 486" on a 386sx board would offer good value for money if you are looking for a speed upgrade.
At the time the 386 was popular I assumed that the SX indicated the data bus was a Single word in width, and the DX meant that it was a Double word (i.e. 32 bits) in width. And I heard or assumed that once those were established the Intel marketing dept (who never really got it) used the same designations for the SuX and cool versions of the 486.
IIRC the first Intel x86 CPU with a built-in math coprocessor was the 80486DX; an external math coprocessor could be used with x86 CPUs up to and including the 80386DX. I have been unable to confirm the existence of an actual "Intel 80286SX" (there is a mention in Intel patent US 5325490 A but I'm pretty sure this is a typo).
g4ugm
Veteran Member
After reading the Wiki page I think you are right. Funny how memory plays tricks with us.
Thanks for your responses. Its for a motherboard I want to keep so any upgrade is better than nothing.