more RAM

[qbasicking]

I want to upgrade my RAM from 4MB to 8MB. I inserted the chips into the slot and turned on my computer, but they didn't register in the memory count. I made sure that the chips were correcly inserted and tried again, still nothing.
How do I get them to register?
Could they be bad chips?
How expensive are RAM cards?

The computer is an 486 Ex Tech (which is IBM compatible). The RAM chips are borrowed from a 286 IBM.

 

[Karl Blessing]

Older computers are VERY picky about memory types, for example I assume you are working with old 72pin Simms. in this case, I had a 486/25 SX , you had to insert memories in pairs (1x1, 2x2, 4x4, so forth) , and the memory had to be non-parity type. are you only sticking in a single 8meg stick, or are you sticking in two 4 meg sticks, simms have to be inserted in pairs, where both pairs are the exact same. Karl Blessing aka kb244{fastHACK}

 

[JohnS9051]

If you are using memory borrowed from a 286 computer then you definately have 30 pin SIMMs.

Without knowing what motherboard you have I can't be sure but most likely you need to fill all of the slots in a bank.
There may be two banks of 4 SIMMs each or one bank of 4 SIMMs. There may also be slots for 72 pin SIMMs.

SIMMs are much more expensive per MB than SDRAM DIMMs.
If you have slots for 72 pin SIMMs I suggest you use them. You will get more "bang for your buck."
Otherwise get four 4MB SIMMs and install them in the same bank. If you have two banks, you can install the four original 1MB SIMMs in the other bank. For a total of 20MB.

If you can still find 1MB SIMMs you could install 4 in one bank and 4 in the other for a total of 8MB.

Remember I said SIMMs are more expensive then DIMMs so be prepared to pay $15 - $20 each for 4MB SIMMs.
I remember paying $20 each for 1MB SIMMs.

You can get them here:

http://www.pcprogress.com/

http://www.memman.com

Hope this helps. Good luck.

John