MiSTer FPGA Forum

I recently built a Dual RAM MiSTer. I have been very much loving using it!!

My issue, when loading the Saturn Dual RAM core, my MiSTer is locking up. The Single RAM core runs great.
From reading some posts, it seemed to point to a bad RAM module. All hardware is new, purchased this month. Both sticks are v3.0 128mb.

I disassembled the MiSTer and reassembled it. Checked and verified the dip switches on the DE-10 were correct for Dual RAM (SW0,SW1,SW2 off and SW3 on).

Running RAM tests, one stick (only 1 populated) seems to be stable at 143 for about an hr, before reporting errors (3-5). If I manually set it to 140, it will run overnight with 0 errors.

The other stick has similar results (pulling the first stick and replacing it with the second). Seems to be stable at 144 for about an hr, before reporting errors (like 3). If manually setting to 140, it will run overnight with 0 errors.

With both sticks installed, similar results. Seems stable at 142 for about an hr, before reporting 3-5 errors. If I manually set to 140, 0 errors overnight.

I have left the MiSTer running 24/7 for several days with 0 issues outside of the Dual RAM core issue.

RAM test running with both sticks while typing the OP. 30ish mins? I will leave it running and post results after 12hr-ish.

0020 144
3 | 000275 - double dash
00000000

0480 143
3 | 39bE
00000000

Time to swap the RAM chips.

30ish mins? I will leave it running and post results after 12hr-ish.

0020 143
3 | 000270 - double dash
00000000

Based upon your test data your memory is working. The last row of your test results are the number of fails, all test are all showing zero fails. You certainly don't need to test for any longer than an hour.

Remember the Saturn core is still very much a work in progress see here for the recent changes: https://github.com/MiSTer-devel/Saturn_ ... mits/main/

Have you also tried the latest unstable Saturn core build?

You can also try other cores that make use of dual ram like dual ram version of the PSX core or the Smash T.V. core (no sound). If they work it is more an issue with the Saturn core then with the ram.

The solution is simple, don’t use dual ram. The core doesn’t primarily use that anymore and obviously it isn’t working right. When done, it will be single ram only so there’s no point in trying dual ram alphas. Disconnect your second ram and be done with it. Sunk cost fallacy and all that.

C-R-T wrote: ↑Sun Jan 28, 2024 1:27 pm

The solution is simple, don’t use dual ram. The core doesn’t primarily use that anymore and obviously it isn’t working right. When done, it will be single ram only so there’s no point in trying dual ram alphas. Disconnect your second ram and be done with it. Sunk cost fallacy and all that.

Core works fine with Dual Ram. You are from past posts biased against anything with dual ram as you clearly feel it will take away CRT usage. Its fine to not want dual ram but try to be less biased against the use of dual ram.

Xbytez wrote: ↑Sun Jan 28, 2024 9:33 am

Have you also tried the latest unstable Saturn core build?

I am currently using the unstable SingleRAM Saturn core without obvious known issues. Love it. Just found it odd that the DualRAM ver won't even load, with others not having that kind of issue with it.

Chris23235 wrote: ↑Sun Jan 28, 2024 10:39 am

You can also try other cores that make use of dual ram like dual ram version of the PSX core or the Smash T.V. core (no sound). If they work it is more an issue with the Saturn core then with the ram.

The Midway Y core was why I decided to build a DualRAM MiSTer. I have not tired it yet, as I understand it is still in an Alpha state and not really playable. Hoping MK will be playable on the MiSTer, eventually. If not, I'm not missing anything as I still have access to the console versions that work fine.

I was unaware of the DualRAM PSX core. Ill look for it and try it out. I don't really use the PSX core, but it is a good place to test.

C-R-T wrote: ↑Sun Jan 28, 2024 1:27 pm

The solution is simple, don’t use dual ram. The core doesn’t primarily use that anymore and obviously it isn’t working right. When done, it will be single ram only so there’s no point in trying dual ram alphas. Disconnect your second ram and be done with it. Sunk cost fallacy and all that.

I haven't even had my MiSTer for a month yet. I don't have a CRT and have no intention of getting one. As far as sunk cost, I have much bigger concerns on how much I spent (and more importantly why). Lets just say, the info about buying a MiSTer in 2024 and what specifically to buy is VERY outdated... Yes, there are recent videos building units, but none of them actually spell out WHAT to buy (whats included with what. Power Supplies. etc)... Everything is scattered across multiple places and LOTS of it hidden in discord (which is near impossible to search for that kind of stuff). When I purchased it, an assembled unit was not avail from reputable sources, or I probably would have went that route.

If I had to do it all over again, knowing what I know now, I would've saved about $100 for the same outcome, but I still would've gone the DualRAM route...

Let me be clear on the overspend, I chose to do that. I could have done more research, but I wanted it NOW. Damn impulse buys. I just wish the info was more accessible in a new user kinda way to avoid that kinda stuff.

Besides, If I wanted to use a CRT, the capacity is still there...

Xbytez wrote: ↑Sun Jan 28, 2024 9:33 am

Based upon your test data your memory is working. The last row of your test results are the number of fails, all test are all showing zero fails. You certainly don't need to test for any longer than an hour.

This is part of my question. You notice the first stick, at 20 mins shows stable at 144, but at about an hr, throws a couple errors. The test resets to 143, where it then remains stable for several hours. The second stick does the same from 143 to 140. Both above the 130 spec?

What speed does the RAM actually run at? Is that core dependent? Is there a place to set max RAM speed?

you dont set a max speed. The fact that the ram counts down is expected in the memory test. It runs if any error occurs it steps down the frequency and tries again. 140 should be ok to run the core.

You do say you got it from

When I purchased it, an assembled unit was not avail from reputable sources, or I probably would have went that route.

so where was this source. Also how many ram chips are present on each stick. 4 ram chip variants are known to cause issues with the saturn core. The standard design of 2 chip ram is better. Its also best to use v2.9 or v 3.0 Ram.

You also dont specify Ram sizes. Are these Dual 128 mb sticks ?

I would be tempted to remove both sticks swap them over and see if the core crashes still. A dual core failing to boot or reseting is the sign of a dual ram fault. I would also try the Midway core if that also resets then you know its a ram issue.

midline_slippy wrote: ↑Mon Jan 29, 2024 6:05 am

What speed does the RAM actually run at? Is that core dependent? Is there a place to set max RAM speed?

Down clocking is a normal operation with the SDRAM test core this is how the SDRAM test core can ascertain the highest stable MHz frequency the memory performs at.

The MHz speed requirement varies per core, see here:

https://github.com/MiSTer-devel/Wiki_Mi ... -use-SDRAM

midline_slippy wrote: ↑Sat Jan 27, 2024 12:30 pm

I recently built a Dual RAM MiSTer. I have been very much loving using it!!

My issue, when loading the Saturn Dual RAM core, my MiSTer is locking up. The Single RAM core runs great.
From reading some posts, it seemed to point to a bad RAM module. All hardware is new, purchased this month. Both sticks are v3.0 128mb.

I disassembled the MiSTer and reassembled it. Checked and verified the dip switches on the DE-10 were correct for Dual RAM (SW0,SW1,SW2 off and SW3 on).

Running RAM tests, one stick (only 1 populated) seems to be stable at 143 for about an hr, before reporting errors (3-5). If I manually set it to 140, it will run overnight with 0 errors.

The other stick has similar results (pulling the first stick and replacing it with the second). Seems to be stable at 144 for about an hr, before reporting errors (like 3). If manually setting to 140, it will run overnight with 0 errors.

With both sticks installed, similar results. Seems stable at 142 for about an hr, before reporting 3-5 errors. If I manually set to 140, 0 errors overnight.

I have left the MiSTer running 24/7 for several days with 0 issues outside of the Dual RAM core issue.

There was something that came to my mind, because I stumbled about it myself. Did you download the unstable DualRam Saturn core from here by chance?

https://github.com/MiSTer-unstable-nigh ... n/releases

The DualRam file here doesn't work, it is only 5 Bytes. It is not a released core but only a placeholder. The file instantly crashes. I didn't realise it myself until I looked at the filesize.

This is the right link from Discord

https://github.com/MiSTer-unstable-nigh ... 1481d9.rbf

From what i saw in the past about the Saturn core and SDram, the issue was not frequency and it was caused by SRG320 new SDram controller he wrote for the core.
SDram that passed Jotegos test could still have issues but mostly older revisions

While the reason for me starting this thread is 100% one-D-ten-T error by the user, the information I gained was worth it!! Thank you for everyone that helped me figure this out!!

FPGA64 wrote: ↑Mon Jan 29, 2024 7:57 am

so where was this source. Also how many ram chips are present on each stick. 4 ram chip variants are known to cause issues with the saturn core. The standard design of 2 chip ram is better. Its also best to use v2.9 or v 3.0 Ram.

You also dont specify Ram sizes. Are these Dual 128 mb sticks ?

I would be tempted to remove both sticks swap them over and see if the core crashes still.

MiSTerAddons
Both Chips 128mb v3.0 Two Chip
This is a main reason I was looking to only user a reputable source.
Unless looking in forums like this, there is no real info about what kind of chips to get and why.

Xbytez wrote: ↑Mon Jan 29, 2024 9:27 am

The MHz speed requirement varies per core, see here:

So, the core sets the speed to those specs? Or just attempts to use those speeds? Ether way, my sticks tested well above those speeds. It was a good read.

Chris23235 wrote: ↑Mon Jan 29, 2024 10:43 am

The DualRam file here doesn't work, it is only 5 Bytes. It is not a released core but only a placeholder. The file instantly crashes. I didn't realise it myself until I looked at the filesize.

DOH!! I cant believe I’m that stupid and didn’t even notice the file was 5kb.

FPGA64 wrote: ↑Mon Jan 29, 2024 12:32 pm

This is the right link from Discord

https://github.com/MiSTer-unstable-nigh ... 1481d9.rbf

AWESOMENESS!!!! Thank You!! I don’t use discord as it requires a phone number to setup.
This core works and runs beautifully!! THANK YOU!!!