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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: severs on May 01, 2018, 04:21:55 AM

Title: A3000D zip ram speed
Post by: severs on May 01, 2018, 04:21:55 AM

I found some 60ns zip ram on Ebay a while back, and just got around to installing it in my A3000D.  And I have the numb thumbs to prove it.  Anyway, the zips I removed were all 80ns except there was one 70ns.  I assume everything ran at 80ns.  So, shouldn't I see some effect in benchmarks?  They all report memory speed exactly the same, in fact a little slower.  It was... disappointing, especially given the sweat and tears involved.  I have DMAC 2 and Ramsey 4.

Thanks

Title: Re: A3000D zip ram speed
Post by: Castellen on May 01, 2018, 07:36:35 AM

Quote from: severs;838878

So, shouldn't I see some effect in benchmarks?

No, simply adding memory that can tolerate a faster access cycle doesn't magically make the computer any faster.  The memory access speed remains the same.

The revision G Ramsey in the A4000 can be set for 'skip mode' which uses four clock cycles instead of five for each access, which provides faster memory performance and you generally need 60nSec memory for that.

Can't do that on the rev D Ramsey in the A3000 though.

View the docs in this utility for more detail:
http://aminet.net/package/driver/other/SpeedRamsey12a

Title: Re: A3000D zip ram speed
Post by: severs on May 01, 2018, 02:53:53 PM

Ok, thanks.  As luck would have it, I saw a Dmac 4 / Ramsey 7 combo on Ebay the other day, and scarfed them up.  So I'll give this a shot again in a few more days

THanks

Title: Re: A3000D zip ram speed
Post by: SpeedGeek on May 02, 2018, 12:45:39 PM

Quote from: Castellen;838880

The revision G Ramsey in the A4000 can be set for 'skip mode' which uses four clock cycles instead of five for each access, which provides faster memory performance and you generally need 60nSec memory for that.

Can't do that on the rev D Ramsey in the A3000 though.

For Ramsey Rev. D you simply change the Ramsey speed jumper J851. This does exactly the same as the skip mode. ;)

Title: Re: A3000D zip ram speed
Post by: Castellen on May 02, 2018, 08:22:40 PM

Quote from: SpeedGeek;838912

For Ramsey Rev. D you simply change the Ramsey speed jumper J851. This does exactly the same as the skip mode. ;)

Interesting point.  That actually controls the DRAM refresh timing, so moving J851 in that way will change refresh time from 9.5µSec to 6.1µSec.  Though there are still 5 clock cycles per memory access, and of course the clock speed remains the same.

Would be good to see the benchmark result of J851 in either position to see the effect.

Title: Re: A3000D zip ram speed
Post by: SpeedGeek on May 03, 2018, 01:13:13 PM

Quote from: Castellen;838917

Interesting point.  That actually controls the DRAM refresh timing, so moving J851 in that way will change refresh time from 9.5µSec to 6.1µSec.  Though there are still 5 clock cycles per memory access, and of course the clock speed remains the same.

Would be good to see the benchmark result of J851 in either position to see the effect.

I just released an updated version of RamseyConfig. You can use it to change the refresh mode but the skip mode is not supported:

http://www.amiga.org/forums/showthread.php?t=69397