Introduction

Today marks the launch of NVIDIA's newest graphics cards: the 7900 GTX, 7900 GT and the 7600 GT. These cards are all based on an updated version of the original G70 design and offer higher performance for the dollar. Today we will see just how much faster the new NVIDIA flagship part is. But first let's take a look at what makes it different.

At the heart of this graphics launch is a die shrink. The functionality of the new parts NVIDIA is introducing is identical to that of the original G70 based lineup. Of course, to say that this is "just a die shrink" would be selling NVIDIA a little short here. In the future, if either NVIDIA or ATI decide to move to TSMC's newly introduced 80nm half-node process, all that would be involved is a simple lithographic shrink. Sure, things might get tweaked a little here and there, but the move from 90nm to 80nm doesn't involve any major change in the design rules. Moving from 110nm to 90nm requires NVIDIA to change quite a bit about their register transfer logic (RTL), update the layout of the IC, and verify that the new hardware works as intended.

The basic design rules used to build ICs must be updated between major process shrinks because the characteristics of silicon circuits change at smaller and smaller sizes. As transistors and wires get smaller, things like power density and leakage increase. Design tools often employ standard components tailored to a fab process, and sometimes it isn't possible to drop in a simple replacement that fits new design rules. These and other issues make it so that parts of the design and layout need to change in order to make sure signals get from one part of the chip to another intact and without interfering with anything else. Things like clock routing, power management, avoiding hot spots, and many other details must be painstakingly reworked.

In the process of reworking the hardware for a new process, a company must balance what they want from the chip with what they can afford. Yield of smaller and smaller hardware is increasingly affecting the RTL of a circuit, and even its high level design can play a part. Making decisions that affect speed and performance can negatively affect yield, die size, and power consumption. Conversely, maximizing yield, minimizing die size, and keeping power consumption low can negatively affect performance. It isn't enough to come up with a circuit that just works: an IC design must work efficiently. Not only has NVIDIA had the opportunity to further balance these characteristics in any way they see fit, but the rules for how this must be done have changed from the way it was done on 110nm.

After the design of the IC is updated, it still takes quite a bit of time to get from the engineers' desks to a desktop computer. After the first spin of the hardware comes back from the fab, it must be thoroughly tested. If any performance, power, or yield issues are noted from this first run, NVIDIA must tweak the design further until they get what they need. Throughout this entire process, NVIDIA must work very closely with TSMC in order to ensure that everything they are doing will work well with the new fab process. As microelectronic manufacturing technology progresses, fabless design houses will have to continue to work more and more closely with the manufacturers that produce their hardware in order to get the best balance of performance and yield.

We have made quite a case for the difficulty involved in making the switch to 90nm. So why go through all of this trouble? Let's take a look at the benefits NVIDIA is able to enjoy.

NVIDIA's Die Shrink: The 7900 and 7600
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  • Regs - Thursday, March 09, 2006 - link

    Or am I going to have to look for myself? Im too lazy Derek. Reply
  • DerekWilson - Thursday, March 09, 2006 - link

    well... since the 7900 GT performs the same as the 7800 GTX ... and the 7800 GT performance relative to the 7800 GTX is well documented :-)

    You're right though, it might have been good to make this more clear.
    Reply
  • Regs - Thursday, March 09, 2006 - link

    So I suspect a 5-10% difference going from a 7800GT to a 7900GT. Reply
  • Phantronius - Thursday, March 09, 2006 - link

    Derek, why are only the first graphs hightling the 7900' series in orange while the rest are totally blue? It makes it hard to compare them to the 7800 series. Reply
  • DerekWilson - Thursday, March 09, 2006 - link

    sorry, we've had some problems with our graphign engine today -- I will make sure to update the colors on the rest of the graphs so they are more readable.

    my plan is to make the new single cards orange and their sli counterparts green.

    I understand that it is a lot of data in one place, but I hope this helps.

    Thanks,
    Derek Wilson
    Reply
  • coldpower27 - Thursday, March 09, 2006 - link


    I though sites reported that the die size of the R580 is supposed to be 313mm2 not 353mm2 as stated in the article???
    Reply
  • APKasten - Thursday, March 09, 2006 - link

    Man, I've been reading this sight for like two years now and they always find a way to make me feel like a noob. Can anyone tell me what 'the IC' is? Didn't see the long form in the article. Reply
  • DerekWilson - Thursday, March 09, 2006 - link

    Sorry ...

    Integrated Circuit.

    It is the term for what is commonly refered to as a "chip"
    Reply
  • APKasten - Thursday, March 09, 2006 - link

    Oh man that's embarassing...for some reason I just couldn't figure that. Sometimes the brain just doesn't work right. Reply
  • 4AcesIII - Thursday, March 09, 2006 - link

    Not an ATI fan anyways but it does seem that these boys favor ATI in almost every review. Now having had experience with ATI it makes me wonder how they can sleep at night knowing what sort of reputation, and consistant reputation ATI has for absolute crap software/drivers. Some of the TV cards they've put out aren't supported by themselves, left to 3rd party software and powervcr at that. Both ATI and Nvidia have good hardware the huge difference between them is implimentation via drivers and software. Nvidia can do it, ATI can't and they've proven it over time. Nvidia drivers are compatible with more of their older cards until you go back to 2mb TNT cards. ATI wasn't able to do this. I don't find Anandtech impartial anymore, they don't put out anywhere near the amount or quality of articles they used to and there's some plagerism claims about them floating around the web. Because of all this I only keep this link for amusement it's not considered a serious source of info anymore. Reply

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