Rybka, Fritz, and Shredder Stand alone chess engine and Gui

If i buy Rybka 4 will it be impossible to use it without a gui?

Also is Fritz 12 an engine and GUI Combined?

What about Shredder 12? 

Where do you get a GUI. Exactly what is a GUI?

Also which one should I get? I want to improve at chess. I don't really care about the rating because they are all highly rated. I am a 1600 USCF Rated player.

GUI is graphic User Interface. You need one, to see wat the engine is doing.

I thik Rybka comes with a GUI called Aquarium?, Not sure, maybe you ave to buy it seperately.

SCID and ARENA are good free GUI's. They will work with Rybka, and other strong engines like Houdini or stockfish.

Fritz has it's own GUI, dont know much about shredder.

I think it's unnecessary to pay money for an engine or GUI, there's so much really good free stuff out there. Scid can do everything really expesive software can do, IMO

Yep, you don't need to pay for Rybka. Stockfish and Houdini are pretty strong, and can work with multiple processors.

Years ago chess programs came with the interface and engine inseperable.

Now  a Universal Chess Interface can be coupled with any engine that meets the UCI specifications. There are a few free UCI intefaces like Arena and many free engines. One of the best of the free engines is Houdini 1.5 .

Many of the engines are extremely powerful. Most important is what you see daily, the UCI. Once you've settled on that you can 'install' and switch between several engines.

I've tried various UCI and in my opinion the best is Shredder. It may not have all the "bells & whistles" of a few but everything works. In some of my other interfaces things did not. I'm particularly interested in analyzing my over-the-board games. Shredder creates a great histogram as it's analyzing and saves to an .epd file any position I choose. Shredder inserts into the analysis text the 'score' in pawns. When the text is printed its easy to follow the changes.

Long ago I stopped struggling with my Fritz 8. It's histogram never worked and it doesn't insert a score into the analysis text ( just those symbols +- ). I don't think it saves to a position file. A friend just bought the latest Fritz 13. We couldn't get the histogram to work and it does not put the score in the text. I gave up on Arena long ago as it was too buggy. I downloaded a trial copy of Aquarium. It would't load my .pgn files. I just bought the latest Hiarcs Explorer. It doesn't creat a histogram ( their Support confirmed ) and I don't think it will save to a position file. It does have a great engine.

Please be relevant, helpful & nice!

This article is ten years old, but it helps to explain the differences between GUIs and engines

http://www.chessbase.com/support/support.asp?pid=213

And yes, for all practical purposes, you need a GUI.  Many are free.  Try them all to see which one you like the best.  WinBoard, Arena, and Tarrasch are all possible choices.  My favorite is now Scid vs. PC.

As far as engines are concerned, the free versions of Houdini, Stockfish, Critter, Spike, and Rybka, among others, are all worthwhile to have.

And yes, Fritz12 and Shredder come with their own GUIs.  (I have them both but I prefer Scid vs. PC over both of them.)