FPM 60ns VS EDO 50ns

[Hyperspeed]

Here's an odd thought that occurred to me just now:

If Amigas cannot utilise the EDO feature of more recent SIMMs would they still benefit from the 50ns rating that these SIMMs occasionally boast?

Here are 4 URLs that discuss problems with EDO:
http://home.cfl.rr.com/eaa/MemoryTypes.htm
http://eab.abime.net/archive/index.php/t-3540.html
http://mail-index.netbsd.org/port-amiga/2003/05/21/0004.html
http://home.swipnet.se/~w-32234/ppcrulez/faq.html

The last reccomends FPM for overall compatibility, would anyone have an opinion here on this matter?

And finally, the first URL discusses that if your motherboard has gold contacts your SIMM should too, if it has tin contacts then the SIMM should have tin contacts.

?

[Hyperspeed]

I pasted a chart on another thread to identify DRAMs on a 72-pin SIMM:

http://www.amiga.org/forums/showthread.php?t=22053

This might help to see if your SIMM is EDO but some Micron DRAMs don't conform to the layout.

I'm surprised you thought the 2x 50ns SIMMs were faster as when you have two SIMMs on a Blizzard the thing should revert down to 70ns shouldn't it?

I know that the DCE SX32-Pro for the CD32 has a jumper allowing a 50ns SIMM. I've never personally come across a 50ns FPM but I do remember back in '95/'96 Amiga Format reviewing the Blizzard 1260 with a 50ns SIMM.

[Hyperspeed]

I wonder if it has something to do with the internal organisation or refresh rate of the DRAMs...

Those SIMMs look EDO to me, the DRAMs are ultra slim. Great for Blizzard boards so long as you get reliability from them.

[Hyperspeed]

According to some Phase5 thing I read, no Amiga accelerator utilises EDO for some techy reason. I would assume this means the Cyberstorm PPC 604 too!

Oddly the Picasso-IV (1996) uses 4MB of EDO for it's video memory.

I think the Blizzard PPCs early menu was to turn on precharge which would help dodgy Korean SIMMs work. It didn't allow Extended Data Out improvement.

And yes, a lot of people have a fetish with putting 256MB on a Blizzard 1230-IV "because it can" but they'll probably never use all that FastMem and it'll revert each SIMM to 70ns. Same for Blizzard 1240 and 1260.

As far as I know the Blizzard PPC has SCSI built in so only has one SIMM slot (?). Odd that a newer type of memory wasn't used for these boards...

One thing I'm thinking about now after having problems with SCSI transfers is that the A1200 trapdoor connector and the 'zebra' connector on the Blizzard 1260 are of different metals. This would mean the oxidisation problem would occur (rapidly given the uncooled nature of the 1260!).

[Hyperspeed]

I will only use FPM type 72-pin SIMMS too.

I ordered a 128MB FPM from OEMPCWorld and the stupid arseholes sent me some EDO SIMM that I could get anywhere much cheaper. I checked, double-checked and triple checked.

I have quoted twice the dipstick there who said "Your machine is too old. Amiga cannot take more than 10MB of memory. I am cancelling your order!"

:-D

Anyway, the QuikPak 4060 gets some serious problems so I've read. Incompatibilities with certain software (Shapeshifter if I remember correctly).

I bought a Blizzard 1230-IV from Power Computing nearly 10 years ago and it came with an ACT single-sided 16MB EDO SIMM and it gave me unreliable performance. I used this in the 1260 I later purchased but later put a Micron single-sided 64MB FPM in and started seeing reliability increase.

I get SCSI problems with the SCSI-IV kit from DCE, I think that might be to do with oxidisation on the contacts. I'll need to clean that up and get the desktop cooled too.