Need help on choosing ZIP RAM for Amiga 3000D

[trixeo]

Hi! I am new to big-box Amiga, I need to upgrade my A3000D with more fast memory. It now has 2MB chip, 4MB fast as ZIP (Static Column Mode) and additionally 4MB of fast as DIP (Page Mode). As I understand it removing the DIPs and filling the ZIP RAM-slots up to 16MB SC would be the best way next to buying a CPU-accelerator card. Vesalia Online sells these "ZIP RAM HYB511000BZ-7 (Set of 4)" - are they Static Column Mode or Page Mode 1MX4? They don't reply on emails :/ As I understand it the general rule is that if the number ends on 00 it's PM, and if 02 it's SC, which in this case then would calculate to PM. SM would be the fastest ones for A3000, right?

[trixeo]

Sorry I forgot to add that you can not mix these types of ram in the A3000

the first ram installed in the first socket tells the motherboard whether it is SC or PM ram

PM at the start can have mixed SC + PM ram in banks

SC at the start ALL chips need to be SC or problems will occur

Az

Thanks! Exactly as I understand it. Yes I am aware that my system now runs in PM, it shows as slower in SysInfo with the DIPs in it. Do you have any ideas as to where to get SC ones?

[trixeo]

Check out utsource.net - I got 32 ZIP RAMs for my A2386SX from there (enough for 8MB on two boards) at a good price.

Can you please tell me the part no.?

[trixeo]

The 3000 requires either 256Kx4 (don't buy those, they're too small and won't mix) or 1Mx4 chips. 511000 sounds like 1Mx1 which won't work.

If you're thinking of getting an '040 or '060 accelerator you can skip SC ZIPs since the burst mode they enable works with '030 only. Best is an accelerator with RAM so you can skip the expensive ZIPs altogether.

Thanks for the input! I got hold of 32 pieces of HM514402BZ6 for $83.63. I am not 100% sure they really are SC though, even though there is that "02" in the prod.no.

[trixeo]

Yes, 514402 are SC.

I just wonder what the BZ in the Hitachi HM514402BZ6 denotes, the 6 is 60ns I guess. The old ones I have in my A3000 says HM514402AZ8 (I have only 8 of them), they too are SC, but 80ns and have that AZ. So AZ vs. BZ, could it be grade maybe?