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iris_raj
03-01-2004, 11:49 PM
Dear All,

What are the advantages of Developing OPENGL in an ONYX2 SGI machine over a intel machine with GeForce Family of Accelrator cards. I was so far working on the latter machine. Now I am going to shift my development in ONYX2 machine. I would be grateful, if some can provide bench marking standards


With regards
IRIS_RAJ

dorbie
03-02-2004, 07:59 AM
I used to use these systems a lot. An SGI ONYX2 used to be an impressive machine, now it is just too old to remain impressive. It cannot match a PC card on transformation and lighting and on fill performance only a system with 4 raster managers per pipe is interesting but not greatly so, anti-aliasing is high performance, but that's about it really. There's no multitexture support, no anisotropic filtering, no combiner support and no programmability either vertex or fragment.

IRIX gives you real-time capabilities and the multiprocessing architecture & bandwidth is nice and of course it's 64 bit but whether that is enough for you depends on your application. Scalability in a single image system is a key feature that PCs still lack and other things like genlock, hyperpipe and video support of various kinds may make it more viable in some areas. 3D textured fill and texture memory capacity may be interesting but these both depend on your raster managers to an extent.

There are one or two features that the system still excells at but it pretty much gets spanked on features and performance by the best PC graphics cards. My advice would be to wait for PCI express and upgrade to a PCI Express system (with MP and 64 bit support if you need it).


[This message has been edited by dorbie (edited 03-02-2004).]

zeckensack
03-02-2004, 09:09 AM
Regarding these "one or two features" that dorbie mentioned, the usual suspects would be pixel path performance, glReadPixels in particular, and (smoothed) wireframes.

dorbie
03-02-2004, 11:39 AM
Pixel path with things like color matrix applied may be one area where iR does well, for vanilla stuff PC's can perform quite nicely too, but I wouldn't agree that AA lines was one area where iR does well. You can get cards with those accelerated very nicely on a PC. It just tends to be crippled on some consumer PC cards. Get a "DCC" board and you'll probably be in good shape for lines. Check the viewperf benchmark results I think CDRS has lots of AA wireframe.