View Full Version : Do GPU's have "steppings"?
With the (alleged) video processor problems with the 6800's, it got me thinking, do GPU chips have different steppings?
Surely nVidia could come out with a later stepping that fixed the problem?
I suppose if we knew what stepping each GPU was, we could work out which ones were the better overclockers. Or do steppings not apply to GPU's?
good question & it would be nice to know the awnser.
i know they 'speed bin' but do not know if this is tied into 'steppings'.
10-22-04, 12:53 PM
I belive its kind of a Yes and No question.
Yes, they tape out a few cores to get it to work properly, however because of the short run of GPU's once they have a working sample they deem fit, they dont change it because its going to be replaced in 6 months?
You could also call the next refresh based on the nv40 core a diffrent 'stepping' so its kinda up to you.
The reason why intel and amd have steppings is because the same core can be used for years, and they have time to fix small bugs/add minor stuff.
10-22-04, 04:01 PM
I'm not sure. Couldnt you almost consider the R300, R350, R360 all different steppings of the same chip. They just did slight improvements it wasnt a whole new core.
Kinda like the P4 where the only differences between the A and B stepping were more L2 and different frontside bus.
One thing is for sure. They definitely bin these chips.
New steppings also contain bug fixes. I've seen A2 stepping of a Quadro FX 2000 so new steppings certainly exist.
10-22-04, 05:13 PM
Yup, there are at leats A0 to A2 steppings for GPU's.
All 6800gt appear to be A1 revision - GPU equivalent term to CPU stepping me thinks. I didn't hear anyone having A0 or A2 revision. PCI-E versions maybe?
10-22-04, 05:48 PM
No, currently nvidia is using a bridge chip for PCI-e, so the cores will all be the same
Thanks all for your helpful answers. It seems that GPU's do have steppings then. I would have been surprised if they didn't. Maybe a new 6800 stepping will be released with the video processor fixed? Who knows...
GPUs do have different revisions which are essentially hot-fixes, tweaks to improve the yields or allow increased operational frequencies.
If I remeber correctly, it took NVidia 5 revisions before releasing the NV20 back in 2001. Later revisions (those used for the Ti series) added PS 1.2 support
Another good example is the NV34. The FX5500 is the latest stepping of the NV34 core. Interestingly enough, the original FX5200 overclocked very well up to 380-400MHz (not bad for a 0,15u GPU), but most NV34B cannot go much higher than 300MHz. It seems that NVidia introduced a new core/revision which is probably cheaper to manufacture, but which has worse frequency scalability (Nobody would buy a 5500U anyway these days...)
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