Thursday, January 5th 2012
AMD Denies Hidden GCN CUs in Tahiti
Over the past few days, we were hearing rumors from many quarters that AMD's "Tahiti" high-performance GPU may have been a deviation from an older specification, and that it really has 2304 stream processors spread across 40 GCN compute units (CUs), instead of the 32 the Radeon HD 7970 ended up with. Both AMD and NVIDIA create more redundant components on their chips than their SKUs end up getting, so they could increase yields, it's a process commonly known as "harvesting".
On Tuesday, AMD quashed the rumor in an e-mail to Bright Side of News, in which it said that Tahiti XT (Radeon HD 7970) makes use of all the CUs there are, on the chip. The 40 CU / 2308 SP rumor gained some weight with the fact that since AMD is venturing into unknown territory (TSMC's 28 nm process, built after quite some delays and failures), it could do some heavy harvesting. Examples of harvesting in recent past include Intel Sandy Bridge-E Core i7 processors, which use only up to 6 out of 8 cores on the silicon, and only up to 15 MB out of 20 MB available on it; and GeForce GTX 480, which used only 480 out of 512 CUDA cores available on the GF100 GPU.
Source:
Bright Side of News
On Tuesday, AMD quashed the rumor in an e-mail to Bright Side of News, in which it said that Tahiti XT (Radeon HD 7970) makes use of all the CUs there are, on the chip. The 40 CU / 2308 SP rumor gained some weight with the fact that since AMD is venturing into unknown territory (TSMC's 28 nm process, built after quite some delays and failures), it could do some heavy harvesting. Examples of harvesting in recent past include Intel Sandy Bridge-E Core i7 processors, which use only up to 6 out of 8 cores on the silicon, and only up to 15 MB out of 20 MB available on it; and GeForce GTX 480, which used only 480 out of 512 CUDA cores available on the GF100 GPU.
52 Comments on AMD Denies Hidden GCN CUs in Tahiti
Has anyone ever heard about a fan boy being disloyal?
Its bad because they are lying to the consumer. Its like saying a car has a 5Ltr turbo charged engine underneath the hood but it really has a 1.8Ltr Diesel. The performance is still good so it doesnt really matter. it just depends how you look at it
They released the specs for the card, they weren't lying to anyone, they didn't say it came with X amount then it ended up being under that amount. And beyond that, have you been watching the news articles over the last week? The 7970's just set world records, not only for bench scores, but for clock speeds. They OC to an insane level, even on air I think what 400mhz OC's on the GPU? Thats a ton of performance just sitting there for free. Plus now they dropped the price.
You are making it too complicated, what it comes down to for hardware is the performance for the price. And the 7970 brings that, despite if it has things locked or not, and if you decide to OC, tack another 20 - 30% performance on for free (how could anyone complain about that?). Of course your previous post made people respond, it was made without any thought.
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If they said they had 2300 ( what ever it was) and 40 rops and it turned out to have less I could see your point, but stating they have 2000 when there is a possibility there is more is not really lying.
It's because silicone can be a fickle thing if they shot for 2000 on the dot they would have hardly any 7970s and they'd all be 7950s.
Pretty much every silicone devices get made with extra components to give them wiggle room :toast:
Means if any do survive 100% they will later be sold when they have enough to distribute them.
:laugh:
It's called guaranteed specification, yeah you may pull more out but it doesn't mean they were duping you or lying to you.
Especially considering those extra 300 shaders probably don't even work if they do exist.
( which according to AMD they don't so they've probably been laser cut)
Although I appreciate this is about semantics so no point taking it past this : ]
Anyway, i'm pretty sure if such a thing exists W1zzard will find it: didn't he find that instance with the ATI card that had less shaders (or whatever it had missing) a while back? I seem to recall another instance where he found nVidia using a 27-something instead of a 25-something which gave their cards an advantage as well but i really don't recall specifics.
At the end of the day, this card performs well and isn't overly expensive.
Took the shitty company over a year to beat the GTX580 which was based on Fermi which again, is over 2 years older, what can I say? AMD = :lmao:
more hidden cores my ass , as someone correctly stated elsewhere it was probably an x2 of a lower GPU that got scrapped or a total press turd to uncover a leak
finding out a card that already performs better than expected could possibly be unlocked for even more performance is kinda like your wife telling you that she's baked a cake wearing a nightie and sent the kids to her mothers house for the night.
as opposed to before where she just baked a cake.
This if anything is amazing pr.
the fact that the gtx 480 had more shaders that were locked didn't bother anyone. The fact that it was 6 months late, sucked more power than a microwave and put out enough heat to keep a 2000 sqft home warm in a subzero temperature winter did.