~ An introduction to RTG
The SiSys RTG is a means for Amiga screens to open in a window on the PC's display. RTG screen modes are then selected just like any other "native" (e.g. PAL, Multiscan, Super72 etc) Amiga screen using the display mode requester/option in most applications. On my system I now have the following screen modes available (this could differ on your system, depending on what resolution the PC is running in):
No matter what you say the RTG is impressive, but it does have limitations. For general Workbench purposes it is fine, but even across a fast Ethernet TCP/IP connection running programs that use large bitmap images can be dead slow. It should also be pointed out that there are a number of problems associated with the RTG that some users might find annoying. These include when dragging icons (or files in DOpus listers) you don't see them, likewise when re-sizing windows you don't see an outline of the window. In both case you have to use your imagination and after dragging/re-sizing when you release the mouse button the icon/window simply appears in the new position/size. I have become use to this and don't really find it a problem, but I'm sure some users might? Another annoying problem is that in order for menu's to be displayed you have to run Magic Menu's. Thankfully if like me you don't like this you can still make menus look/behave in the same way that standard intuition menu's do. The one thing that makes up for this is the fast solid window dragging. Even on a cheap PC graphics card the window dragging is just so fast and smooth it puts Amiga graphics cards to shame! Another potential problem with the Amiga display on the PC is that should the PC crash (or just the Siamese) although the Amiga is still running, you will be "left in the dark" with no means of saving your work on the Amiga. Hmm, best just remember to keep saving stuff!
~ Compatibility
If you run lots of old Amiga software that does not follow Commodores guidelines then you will have lots of problems. Even some newer programs (e.g. GoldED, Cinema4D to name just two) do have problems when running on a RTG screen. Others including Photogenics, YAM (not 2.0) and DOpus work just fine. Once running (and therefore having patched quite a few things) the RTG seems to effect the backdrops (and more...) on all screens. I have found this to cause a few problems :( On an AGA based Amiga (A1200/A4000) the RTG allows Workbench and many other applications to open in a 256 colour (or higher) display. Although not having first hand experience of the SiSys running on an ECS based Amiga (A2000/3000 etc) I have heard of many problems when using RTG. The two most common are that the Workbench will not RTG and those screens that will are still limited to 16 colours! Paul/Steve any chance you could clarify this situiation? Okay so you can't play ADoom on a RTG screen - but so what! If you've got a fast PC, a 3Dfx card  and a copy of Quake II, Unreal, Sin or Half-life - why on earth should you want to play ADoom (no dis-respect to Peter McGavin intended!). Another example... The RTG allows you to run an Amiga browser (e.g. IBrowse or VoyagerNG) in 8-bit (or greater) but loading all of those bitmaps will grind it to a halt! Yet again what's the point when you could use IE or Navigator? None! The RTG certainly looks great and when you think about what it's doing it is amazing, but you will have to give up some of your older (and possibly favourite?) Amiga applications. It does have it's uses, but at the same time it does have problems. Read the FAQ/Troubleshooting section on this page for details on some other RTG "problems".
~ Cybergraphics
The SiSys RTG claims to have implemented around 60% Cybergraphics compatibility. Shipped with the SiSys, hidden in the libs directory in SiSys: there is a library that is called cybergraphics.library. This library is not the "real" cybergraphics.library, but infact a fake. It does not get a mention in the manual, but Paul has given me this explination of how the RTG works: The cybergraphics.library is a "fake" and this only contains stubs (the actual code is kept in the RTG file). RTG first trys to open the real cybergraphics.library (from libs:). If it opens, this means CGFX is running (on a Cybervision etc) and I install my patches over the top. If it is not found, it then loads the "fake" one in the SiSys:libs/ directory, then patches that as normal. From then on, as the library becomes resident, all other apps will now find my library when they try and open cybergraphics. However if RTG isn't running, other apps wont be able to open cybergraphics.library, which avoids confusion/crashes and for this reason it must not be copied to libs:
~ Workbench on an RTG screen
Below is an example of how impressive Workbench looks when running on the PC's display.