@saod9 wrote:i have deep rybka 3 and iwana to buy deep4 is that good for chess computer champions...
thanksss.
"Deep Rybka 3" is just the normal Fritz 11 GUI (re-branded) with the Deep Rybka 3 engine file included.
"Deep Rybka 4" is just the Fritz 12 GUI with the Deep Rybka 4 engine file included.
So if you are happy with the Fritz 11 style GUI that comes with Deep Rybka 3 then there is no need to get Deep Rybka 4. The Fritz 12 GUI is the new "ribbon" style GUI but it doesn't do anything new. All you would gain is the Deep Rybka 4 engine, which is a tiny file you can just add to your Deep Rybka 3.
By the way regarding the engine, Houdini 3 Pro is much stronger than Deep Rybka 3 or Deep Rybka 4 engine. You can use Houdini 3 engine in either DR3 or DR4 GUI.