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.

Efficiency Gets Another Boon: Parallel Kernel Support The RV770 Lesson (or The GT200 Story)
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  • SiliconDoc - Thursday, October 1, 2009 - link

    Jeezus, you're just that bright, aren't you.
    The article is dated September 19th, and "they scored a picture" from another website, that "scored a picture".

    Our friendly reviewer herer at AT had the cards in his hands, on the bench, IRL.
    --
    I mean you have like no clue at all, don't you.
  • palladium - Thursday, October 1, 2009 - link

    I agree. GPGPU has come a long way, but it's still in its infancy, at least in the consumer space (Badaboom and AVIVO both had bugs).

    I just want a card that can play Crysis all very high 19x12 4xAA @60fps. Maybe a dual-GPU GT300 can deliver that.
  • wumpus - Wednesday, September 30, 2009 - link

    First first reaction after reading that the cost of double multiply would be twice that of a single was "great. Half the transistors will be sitting there idle during games." Sure, this isn't meant to be a toy, but it looks like they have given up the desktop graphics to AMD (and whenever Intel gets something working). Maybe they will get volume up enough to lower the price, but there are only so many chips TMSC can make that size.

    On second thought, those little green squares can't take up half the chip. Any guess what part of the squares are multiplies? Is the cost of fast double point something like 10% of the transistors idle during single (games)? On the gripping hand, makes the claim that "All of the processing done at the core level is now to IEEE spec. That’s IEEE-754 2008 for floating point math (same as RV870/5870)". If they seriously mean that they are prepared to include all rounding, all exceptions, and all the ugly, hairy corner cases that inhabit IEEE-754, wait for Juniper. I really mean it. If you are doing real numerical computing you need IEEE-754. If you don't (like you just want a real framerate from Crysis for once) avoid it like the plague.

    Sorry about the rant. Came for the beef on doubles, but noticed that quote when checking the article. Looks like we'll need some real information about what "core level at IEEE-754" means on different processors. Who provides all the rounding modes, and what parts get emulated slowly? [side note. Is anybody with a 5870 able to test underflow in OpenCL? You might find out a huge amount about your chip with a single test].
  • SiliconDoc - Wednesday, September 30, 2009 - link

    I think I'll stick with the giant profitables greens proven track record, not your e-weened redspliferous dissing.
    Did you watch the NV live webcast @ 1pm EST ?
    ---
    Nvidia is the only gpu company with OBE BILLION DOLLARS PER YEAR IN R&D.
    ---
    That's correct, nvidia put into research on the Geforce, the whoile BILLION ati loses selling their crappy cheap hot cores on weaker thinner pcb with near zero extra features only good for very high rez, which DOESN'T MATCH the cheapo budget pinching purchasrs who buy red to save 5-10 bang for bucks...--
    --
    Now about that marketing scheme ?
    LOL
    Ati plays to high rez wins, but has the cheapo card, expecting $2,000 monitor owners to pinch pennies.
    "great marketing" ati...
    LOL
  • PorscheRacer - Wednesday, September 30, 2009 - link

    Just so you know, ATI is a seperate division in AMD (the graphics side obviously) and did post earnings this year. ATI is keeping the CPU side of AMD afloat in all intents and purposes. Is there a way to ban or block you? I was excited to read about the GF300 and expecting some good comments and discussion about this, and then you wrecked the experience. Now I just don't care.
  • Adul - Thursday, October 1, 2009 - link

    silicon idiot is doing more harm than good. please ban him
  • SiliconDoc - Thursday, October 1, 2009 - link

    The truth is a good thing, even if you're so used to lies that you don't like it.
    I guess it's good too, that so many people have tried so hard to think of a rebuttal to any or of all my points, and they don't have one, yet.
    Isn't that wonderful ! You fit that category, too.
  • SiliconDoc - Wednesday, September 30, 2009 - link

    Do you think yhour LIES will pass with no backup ?
    " A.M.D. has struggled for two years to return to profitability, losing billions of dollars in the process.

    A.M.D., the No. 2 maker of computer microprocessors after Intel, lost $330 million, or 49 cents a share, in the second quarter. In the same period last year, it lost $1.2 billion, or $1.97 a share.

    Excluding one-time gains, A.M.D. says its loss was 62 cents a share. On that basis, analysts had predicted a loss of 47 cents a share, according to Thomson Reuters. Sales fell to $1.18 billion, down 13 percent. Analysts were expecting $1.13 billion."
    ---
    http://www.nytimes.com/2009/07/22/technology/compa...">http://www.nytimes.com/2009/07/22/technology/compa...

    ATI card sales did increase a bit, but LOST MONEY anyway. More than expected.
    --
    PS I'm not sorry I've ruined your fantasy and expsoed your lie. If you keep lying, should you be banned for it ?
  • PorscheRacer - Thursday, October 1, 2009 - link

    http://arstechnica.com/hardware/news/2009/07/intel...">http://arstechnica.com/hardware/news/20...-graphic...

    Again, the graphics group of AMD turned a profit (albeit a small one after R&D and costs) while the other divisions lost money.
  • SiliconDoc - Thursday, October 1, 2009 - link

    LOL- YOU'VE SIMPLY LIED AGAIN, AND PROVIDED A LINK, THAT CONFIRMS YOU LIED.
    It must be tough being such a slumbag.
    --
    " After the channel stopped ordering GPUs and depleted inventory in anticipation of a long drawn out worldwide recession in Q3 and Q4 of 2008, expectations were hopeful, if not high that Q1’09 would change for the better. In fact, Q1 showed improvement but it was less than expected, or hoped. Instead, Q2 was a very good quarter for vendors – counter to normal seasonality – but then these are hardly normal times.
    Things probably aren't going to get back to the normal seasonality till Q3 or Q4 this year, and we won't hit the levels of 2008 until 2010."

    As you should have a clue, noting, 2008 was bad, and they can't even reach that pathetic crash until 2010.
    An increase in sales from a recent prior full on disaster decrease, is still less than the past, is low in the present, and is " A LOSS " PERIOD.
    You don't provide text because NOTHING at your link claims what you've said, you are simply a big fat LIAR.
    Thanks for the link anyway, that links my link:
    http://jonpeddie.com/press-releases/details/amd-so...">http://jonpeddie.com/press-releases/det...ntel-and...

    This is a great quote: " We still believe there will be an impact from the stimulus programs worldwide "
    LOL
    hahahhha - just as I kept supposing.
    " -Jon Peddie Research (JPR), the industry's research and consulting firm for graphics and multimedia"
    ---
    NOTHING, AT either link, describes a profit for ati graphics, PERIOD.

    Try again mr liar.

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