Sega Saturn Rhea review

Most videogame journalists and critics will agree that there isn’t enough being done to try and preserve and archive videogames and their history. As thousands of older titles languish in copyright limbo, preventing a re-release on more modern hardware, the retro consoles that can run these relics are getting older and more prone to hardware issues. Furthermore, the humble CD, once marketed and promoted as being nearly indestructible, has proven to be less reliable over long periods of time than was originally thought. It’s not all bad news though, as we have seen in the past, once a machine reaches the end of its commercial life, dedicated fan communities of hackers and homebrew developers step up to keep the hardware alive. The Rhea is one such home-developed device, designed to extend the life of the 2D powerhouse that is the Sega Saturn. Thanks to some amazing hardware engineering by the super talented Deunan Knute (who also produced the first working Dreamcast optical drive emulator), it’s now possible to replace the optical drive in a Sega Saturn with a device that uses SD cards. This device appears to the Saturn just as if it were a regular CD drive, meaning you can now load all your Sega Saturn games from the much more reliable and modern media of SD. We were recently contacted by a customer who was lucky enough to obtain one of these sought after upgrades and wanted us to fit and test it for him. Sensing an opportunity I arranged to borrow the console for a few days to bring you this review.

Rhea, you got to see her

Saturn with Rhea installed.
Saturn with Rhea installed.

Named after one of the moons of the planet Saturn, the Rhea board fits snugly inside your Saturn console rather than orbiting around it. Hardware installation is relatively easy once the CD drive itself is removed, there aren’t even any wires to solder on the latest design. Of course, if you don’t fancy doing the job yourself you can always send it to us for installation and testing. With the CD drive removed and Rhea fitted in its place, there’s a lot of empty space around the inside of the console, including under the Rhea board itself, so you need to take care when inserting or removing the SD card not to drop it. If you do, you may need to unplug the console and give it a gentle shake to persuade your SD card to return to you.

Making images

To use the Rhea you will need to convert your existing Saturn software into image files suitable for use on the unit. Thanks to a long overdue change in UK law we can now do this perfectly legally in our great country. In order for this to work correctly, you will need a PC with an optical drive and some specialist software, since the standard ISO format isn’t generally accurate enough for use with a device like this. Currently, the only program that’s confirmed as being able to create working images for use with the Rhea is Padus DiscJuggler. When using DiscJuggler you must make sure the following options are enabled when you create the image:-

  • Scan gaps/Indexes
  • R-W (CD+G)
  • PQ
  • RAW read


Despite our best efforts, we weren’t able to create a working image using either Alcohol 120% (MDF/MDS format) or Clone CD (CCD format). Given that some CloneCD images available on the internet do work with the device, we can only assume this is a Rhea firmware related bug. We’ve been in touch with Deunan about these issues and he is investigating, so it’s very likely this will be fixed in a future firmware update. The DiscJuggler software is still available from Padus Software here, but it appears to be unsupported and no longer developed.

Setting out the SD card

When you have your image files, you simply need to copy them onto your SD card according to the instructions here. In a nutshell, you create numbered directories for each image starting at 01 (or 02 if you don’t want the Saturn to auto-boot) and then place your image files in the directories accordingly. While you can use bigger SD cards and store lots of images, remember that there’s no GUI on the Saturn to help you select your games, so you will need to remember what goes in each slot.

It’s also possible to add a small ini file to the root of the card and activate some extra options. You can read about all the available options on this page. Most significantly, there’s an automatic region patcher and an automatic 50/60hz switch. The auto region patch basically removes the need for a region free BIOS or similar mod, allowing games from any region to boot on any console. The region patcher will work in any Rhea equipped Saturn but the 50/60hz functionality requires some extra soldering. Rather than use this feature, our customer had opted for a switchless mod instead, giving him the flexibility to play compatible PAL titles in 60hz too.

After testing our unit, we also advise the following settings be added to the Rhea.ini

detect_time = 1000
open_time = 1000

These settings affect how the Rhea emulates the opening of the CD drive and the swapping of a CD. Since the Rhea appears just like a regular optical drive to the Saturn hardware, the console still expects the discs to be changed. With the default detect and open times, we found our console wasn’t sensing that discs had swapped at all. This made for some spectacular crashes and horrible garbled audio among other unwanted effects. Bumping up the open and detect times to those values solved all the problems and allowed for smooth image swapping.

Operating the Rhea

As stated earlier in the review, the Rhea appears just like an optical drive to the Saturn. There’s no GUI front-end so to change image you simply press a button on the Rhea board. This cycles through the images in the various folders you set up on the SD card. You can press the button to change image at any time. If you do this while a game is loading, the Saturn will reset as if you have opened the drive door (if it does not, you likely haven’t set the detect and open times high enough). You can also remove the SD card without needing to power down your Saturn and swap it for another one.

Tested games and performance

Close up showing the SD card inserted into the Rhea.
Close up showing the SD card inserted into the Rhea.

For testing, we reached out to other Saturn users on the popular Sega Saturn UK forum and asked them which games they felt would be the best test of the devices abilities.

Myst – Suggested by Mik on the Sega Saturn UK forums, the game needs to stream FMV and graphical data quite often as you walk around. No problems whatsoever with the game and the loading times were very quick.

Resident Evil – Suggested by Smithyz on the Sega Saturn UK forums, this game is known to have very long load times between rooms if your Saturn laser isn’t clean and perfectly aligned. On the Rhea, while we wouldn’t exactly call the transitions quick, there certainly were no problems.

Strahl – Suggested by Yart on the Sega Saturn UK forums, this is one of those games that’s basically one long QTE, like Road Avenger. I’m no fan of these games but it’s a good test of the devices handling of a game that has heavy and frequent disc access. The game worked fine, no sign of stutter or any problems with the FMV, though my lack of Japanese language skills prevented me from getting very far in the game.

Wipeout – Again suggested by Mik as a game that uses CD audio – Flawless operation as expected.

Other games I tried included Baku Baku Animal, NBA Jam, Psychic Assassin Taromaru, Saturn Bomberman and Battle Garegga, all of which worked perfectly.


The Rhea is a marvellous little device. By removing the single most unreliable component from the Saturn, Deunan has extended the useful life of thousands of consoles around the world. For this reason alone, retro gamers and videogame historians should salute him. There are a few tiny negative points we should point out. Firstly, as noted above, currently the Rhea is super picky about what images it will load and if you want to legally format shift your own Saturn games, you need the help of some unsupported software (DiscJuggler). Secondly, the current batch of Rhea boards is only compatible with Saturns using a 20 pin CD drive. Only earlier models of the console use this type of drive, meaning the Rhea doesn’t work with the majority of consoles on the market. It’s highly likely that both of these problems are temporary however and Deunan has already stated he is working on 21 pin compatibility.

Finally, and we really are nitpicking this time, in an ideal world we would have preferred a device that could use USB mass storage and present a game launcher/image selector program, allowing for large libraries of Saturn games to be stored on the console without the need to go back and forth to your PC. Especially if you don’t have your PC in the same room as your Saturn it can prove quite tedious going back and forth to copy the games you want to use. Of course, smaller SD cards are very cheap now, so you could just buy 10 or so cards and keep your favourite games permanently copied onto them. Deunan explained on his blog that programming a front-end for the Rhea would be difficult, perhaps impossible, since the Saturn’s main CPUs do not have direct access to the CD mechanism. Perhaps a device with its own little screen and image selector software would be possible, but would end up being much more expensive. We’re absolutely nitpicking here, Krikzz and his Everdrives have spoiled us and honestly we’re in awe that the Rhea even exists as it is. Deunan really has delivered an incredible upgrade for Saturn owners and we thank him from the bottom of our hearts.

The Rhea is available now for 20 pin Saturn consoles from this website. If you require fitting services we can arrange this for you, please contact us for more details. While we do offer a fitting service for the unit, we received no discounts or other financial incentives for this review.

See a video of the Rhea in action by clicking here.

24 thoughts on “Sega Saturn Rhea review

  1. Dee says:

    Hi, great information supplied. Is the ODE region free? If so do I have to re-configure to play different regions each time if I have, lets say a Pal Saturn?


  2. Elroheran says:

    Hello, thank you very much for your nice review! I recently received my own Rhea and created an image from Virtua Fighter 2 (PAL) with DiscJuggler according to your video instructions. Even though the game starts perfectly I do not hear any background music in the game only sound effects are present. When I load the cdi-Image in an Emulator the BGM is there but not when loading it through the Rhea. I do encounter this problem also with other Games. My Saturn is a European PAL and Rhea FW is on 3.4.0. Any ideas?
    Thanks in advance and best regards

      • Elroheran says:

        I’ve found the problem in the meantime: “Bad cable connection”
        When fiddling around with the cable while the game was running I realized that some of the 20pins connected to the Rhea had no contact what was the cause for the missing BGM even though the rest of the game was working.
        BTW: A bad cable connection can also could also the cause for Rhea recognizing the image as an Audio CD.

  3. Julio says:

    is there any way u can post it on ebay or anywhere else to post to see how much you can charge over your service if you can really appreciate it if you can do it would be worth it would be worth it

  4. Lee Ashcroft says:


    Great video and blog, it gave me a lot of valuable info. My Rhea has just arrived today and I was hoping that you could let me know before I go ahead with the installation. Is the firmware already flashed to the Rhea or is this something I will have to do before I setup the SD card with the games folders and the .ini file?


  5. Ruaidhri says:

    One… well, two other questions. Roughly what size it the image that comes off the Saturn discs and for a game like Panzer Dragoon Saga, would it still necessitate 4 SD cards as the Rhea wouldn’t know to go to the ‘next available’ disc?

    Going to raid shoe boxes for old SD cards and any spare change too…

    • BuckoA51 says:

      Usually about 650 megabytes for a CD image. You don’t need 4 SD cards, see under “Operating the Rhea” specifically “There’s no GUI front-end so to change image you simply press a button on the Rhea board. This cycles through the images in the various folders you set up on the SD card.”

  6. cleeg says:

    I’m very pleased to say that this is my Saturn, and it’s a really nice piece of kit. The region and Hz mod also works like a charm and I must say how pleased I am with the work and service of the Video game Perfection staff. I’ve used them twice now and they are my go to guys for anything more complex than I can handle, namely this region mod.

    The image making process and operation of the device is a little fiddly, but some clever sort may one day come up with a GUI based system. If not, I don’t mind; I can always keep a small piece of paper with the games’ slots nearby!

    Highly recommended, and the guy who built this system is very friendly and helpful too.

  7. Ruaidhri says:

    …I suppose the reason I’m asking is because one day I’d like to do the Shining Force III trilogy one day!

  8. Ruaidhri says:

    130 bones?!? Looks like something I’ll have to save for!

    Any idea what it would mean for homebrews? I know I have a chipped and modded console but what could you make an original PAL console do?

    • BuckoA51 says:

      Homebrew boots just fine on the Rhea, typically you can use ISO format for that. No modchip is required to use the Rhea either. The only thing you need is some sort of 50/60hz switch (unless you want to play all your games in PAL of course).

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