DOS Games Discussion

[McFly]

I have a 486 baby AT motherboard with a 33 MHZ Bus and a 486 DX-2 66 chip with 33 Mhz Bus Speed. It keeps crashing and I think it's because of the old ram I'm trying to use. The motherboard is supposed to support both EDO and FPM, but which kind do I want for my 486? Does it matter what the refresh rate of my ram is?

And don't ask me to look at my manual, because I don't have one, and don't ask me to look for a manual online, because I've been doing that for the past 8 months.

[Wally*Won_Kenobie]

ERR EDO and FPM??

Yes it does matter what the refresh rate for your ram is.

[McFly]

Thank you for replying.

Would you happen to have any idea of what the refresh rate for a 486 dx-2 66 would be?

[Guest]

70 ns

[Guest]

Oh yeah, slower is safer anyway. If you have a choice between 60 ns and 70 ns, and you're not sure, choose 70 ns and it should be about 99% ready to work properly.

Fast Page RAM typically runs at 70 ns while EDO RAM can do 60 ns. SDRAM can go at about 12 ns, 10 ns, 8 ns, 6 ns, and maybe faster. 30-pin RAM might go at about 100 ns.

Essentially, to be safe, set the RAM timing to the highest possible number. If you are a stunt man, go ahead and try lower numbers to speed your computer up. If you set it too fast, it should crash/lock-up, and then you should be able to reboot, go into the BIOS setup, and set a slower setting. Of course you could do trial-and-error if you have the patience.

[kreats]

When they give a speed rating on the chip, that is the max speed it will operate at - they aren't saying it is designed to run at 70ns for example. Much like you can use PC133 SDRAM in a PC100 system. I'd say go for 60ns just to be sure.

EDO is faster than FPM, but only if it is supported by your motherboard (http://www.oempcworld.com/support/What_is_EDO_Memory.htm). If in doubt, use FPM. Do a memtest if you are concerned about the memory being good.

You can get 60ns FPM btw.