NVIDIA's Fermi: Architected for Tesla, 3 Billion Transistors in 2010
by Anand Lal Shimpi on September 30, 2009 12:00 AM EST- Posted in
- GPUs
ECC Support
AMD's Radeon HD 5870 can detect errors on the memory bus, but it can't correct them. The register file, L1 cache, L2 cache and DRAM all have full ECC support in Fermi. This is one of those Tesla-specific features.
Many Tesla customers won't even talk to NVIDIA about moving their algorithms to GPUs unless NVIDIA can deliver ECC support. The scale of their installations is so large that ECC is absolutely necessary (or at least perceived to be).
Unified 64-bit Memory Addressing
In previous architectures there was a different load instruction depending on the type of memory: local (per thread), shared (per group of threads) or global (per kernel). This created issues with pointers and generally made a mess that programmers had to clean up.
Fermi unifies the address space so that there's only one instruction and the address of the memory is what determines where it's stored. The lowest bits are for local memory, the next set is for shared and then the remainder of the address space is global.
The unified address space is apparently necessary to enable C++ support for NVIDIA GPUs, which Fermi is designed to do.
The other big change to memory addressability is in the size of the address space. G80 and GT200 had a 32-bit address space, but next year NVIDIA expects to see Tesla boards with over 4GB of GDDR5 on board. Fermi now supports 64-bit addresses but the chip can physically address 40-bits of memory, or 1TB. That should be enough for now.
Both the unified address space and 64-bit addressing are almost exclusively for the compute space at this point. Consumer graphics cards won't need more than 4GB of memory for at least another couple of years. These changes were painful for NVIDIA to implement, and ultimately contributed to Fermi's delay, but necessary in NVIDIA's eyes.
New ISA Changes Enable DX11, OpenCL and C++, Visual Studio Support
Now this is cool. NVIDIA is announcing Nexus (no, not the thing from Star Trek Generations) a visual studio plugin that enables hardware debugging for CUDA code in visual studio. You can treat the GPU like a CPU, step into functions, look at the state of the GPU all in visual studio with Nexus. This is a huge step forward for CUDA developers.
Nexus running in Visual Studio on a CUDA GPU
Simply enabling DX11 support is a big enough change for a GPU - AMD had to go through that with RV870. Fermi implements a wide set of changes to its ISA, primarily designed at enabling C++ support. Virtual functions, new/delete, try/catch are all parts of C++ and enabled on Fermi.
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rennya - Friday, October 2, 2009 - link
Go ask the administrator to check my IP and they can verify that my IP comes from a SE Asia country. Are you accusing me of lying for claiming that I come from a nirvana where 5870 GPU is plentiful?Is that all you can do?
Fact - 5870 is not paper launch. You cannot even deny this.
Ah, BTW, English in SE Asia is the same as the ones used in America and Europe.
Totally - Friday, October 2, 2009 - link
Seriously, what are you on? It has to be some good stuff. I want some.I like how you go on and on spouting nonsense about how GT300 has 50% more theoretical bandwith, but without clock speeds there is no way to gauge how much of it will be saturated. In plain speak: Without hard numbers BANDWIDTH ALONE MEANS NOTHING. Sure nvidia has tons of road but we have no idea what they are going to drive on it.
About the 5870 being a paper launch, my best friend had his since the 30th. Day the 5850 launched, took a look over at newegg at 7 in the evening they where there available to order. And still you can order/go to the store and purchase either right now!!! That's not a paper launch. Last time I checked a paper launch is when a product goes live and it's unavailable for over a month.
lyeoh - Friday, October 2, 2009 - link
Doesn't look like good stuff to me. You'd probably get brain damage or worse.Should be banned in most countries.
SiliconDoc - Wednesday, September 30, 2009 - link
When anand posts the GD bit width and transistor count, and mem, then CLAIMS bandwith is NOT DOUBLE, it is CLEAR the very simple calculation you 3rd graders don't know is AVAILABLE.---
IT'S 240 GB !
4800x384/8 !
duhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
It's not FUD, it's just you people are so ignorant it's EASY to have the wool pulled over your eyes.
Lightnix - Wednesday, September 30, 2009 - link
4800mHz x 384 / 8 = 230400mB/s = 230.4GB/sOr 50% faster than 153GB/s - still a big gap but clearly not even nearly double.
It's not FUD, it's just you trolls are so bad at maths you can't even use a calculator to do basic arithmetic with it's EASY to have the wool pulled over your eyes.
SiliconDoc - Wednesday, September 30, 2009 - link
The author claimed not double the former GT200, sir.In the 5870 review just the other day, the 5870 had a disappointing 153+ bandwith, vs the 115 of the 4780 or 124 of the 4890.
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So you can see with the 5870 it went up by not much.
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In this review, the former GT200 referred to has a 112, 127, 141, or 159 bandwith, as compared to the MYSTERY # 240 for the GT300.
So the author claims in back reference to the ati card the nvidia card "also fails" to double it's predecesor.
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I have a problem with that - since this new GT300 is gonig to be 240 bandwith, nearly 100 GB/sec more than the card the author holds up higher and gioves a massive break to, the one not being reviewed, the ati 5870.
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It's bias, period. The author could fairly have mentioned how it will be far ahead of it's competition, and be much higher, as it's predecessor nvidia card was also much higher.
Instead, we get the cryptic BS that winds up praising ati instead of pointing out the massive LEAD this new GT300 will have in the bandiwth area.
I hope you can understand, but if you cannot, it's no wonder the author does such a thing, as it appears he can snowball plenty with it.
UNCjigga - Thursday, October 1, 2009 - link
STFU you stupid moron. There's no "bias". The 5870 has a full, in-depth, separate review with full benchmarks. The author didn't do direct comparisons because THERE IS NO CARD TO COMPARE IT WITH TODAY. FERMI ONLY EXISTS ON PAPER--the mere existence of engineering samples doesn't help this review. The author even indicated he wished he had more info to share but that's all Nvidia allowed. How about we wait until a GT300 ships before we start making final judgements, ok?SiliconDoc - Thursday, October 1, 2009 - link
Good job ignoramus.http://www.fudzilla.com/content/view/15762/1">http://www.fudzilla.com/content/view/15762/1
Oh, look at that, you're 100% INCORRECT.
Another loser idiot with insults and NOTHING ELSE but the sheepled parrot mind that was slammed into stupidity by the author of this piece.
Great job doofu.
ufon68 - Thursday, October 1, 2009 - link
Wow, you must be the biggest fanboy i've ever seen. It would be funny if it wasn't so sad you're vasting so much energy on such insignificant issue and everyone around here just thought to themselves..."what a total failure".But hey, on the bright-side, you made me jump off that fence and register, so you might not be as useless as you seem.
monomer - Thursday, October 1, 2009 - link
Wow, your proof that Fermi exists is a photo of Huang holding up a mock-up of what the new card is going to look like?If that was a real card, and engineering samples existed, why isn't it actually in a PCI-e slot running something? Why were no functioning Fermi cards actually shown at the conference? Why was the ray-tracing demo performed on a GT200?
Finally, why did Huang say that cards will be ready in "a few short months", if they are actually ready now?
You need to calm down a little. You also need to work on your reading skills and to stop making up controversies where none exist.
Yes, Anand pointed out that the memory bandwidth did not double, but in the very same sentence, he mentions that it did not double for the 5870 either.