The Last Bout of ‘03 – NVIDIA’s GeForce FX 5700 Ultra
by Derek Wilson on October 23, 2003 9:30 AM EST- Posted in
- GPUs
Architecture
There was a great deal of talk about why architectural decisions were made, but we will concern ourselves more with what exists rather than why this path was chosen. Every architecture will have its advantages and disadvantages, but understanding what lies beneath is a necessary part of the equation for developers to create efficient code for any architecture.
The first thing of note is NVIDIA's confirmation that 3dcenter.de did a very good job of wading through the patents that cover the NV3x architecture. We will be going into the block diagram of the shader/texture core in this description, but we won't be able to take quite as technical a look at the architecture as 3dcenter. Right now, we are more interested in bringing you the scoop on how the NV36 gets its speed.
For our architecture coverage, we will jump right into the block diagram of the Shader/Texture core on NV35:
As we can see from this diagram, the architecture is very complex. The shader/texture core works by operating on "quads" at a time (in a SIMD manner). These quads enter the pipeline via the gatekeeper which handles managing which ones need to go through the pipe next. This includes quads that have come back for a second pass through the shader.
What happens in the center of this pipeline is dependent upon the shader code running or the texturing operations being done on the current set of quads. There are a certain few restrictions on what can be going on in here that go beyond simply the precision of the data. For instance, NV35 has a max of 32 registers (less if higher precision is used), the core texture unit is able to put (at most) two textures on a quad every clock cycle, the shader and combiners cannot all read the same register at the same time, along with limits on the number of triangles and quads that can be in flight at a time. These things have made it necessary for developers to pay more attention to what they are doing with their code than just writing code that produces the desired mathematic result. Of course, NVIDIA is going to try to make this less of a task through their compiler technology (which we will get to in a second).
Let us examine why the 5700 Ultra is able to pull out the performance increases we will be exploring shortly. Looking in the combiner stage of the block diagram, we can see that we are able to either have two combiners per clock or complete two math operations per clock. This was the same as NV31, with a very important exception: pre-NV35 architectures implement the combiner in fx12 (12 bit integer), NV35, NV36, and NV38 all have combiners that operate in full fp32 precision mode. This allows two more floating point operations to be done per clock cycle and is a very large factor in the increase in performance we have seen when we step up from NV30 to NV35 and from NV31 to NV36. In the end, the 5700 Ultra is a reflection of the performance delta between NV30 and NV38 for the midrange cards.
If you want to take a deeper look at this technology, the previously mentioned 3dcenter article is a good place to start. From here, we will touch on NVIDIA's Unified Compiler technology and explain how NVIDIA plans on making code run as efficiently as possible on their hardware with less hand optimization.
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Anonymous User - Thursday, October 23, 2003 - link
Ever hear of journalistic integrity? He has a responsibility to be objective. He replies "also, there were no glaringly unplayable image quality issues on either side of the line."What a political answer - glaringly unplayable image quality issues? A $499 card shouldn't have any unplayable issues, heck even a $99 card should be playable.
He's dodging the issue about playable image quality issues - missing or lower quality lighting effects for example. The point is that Nvidia has been caught lowering imager quality - removing the eye candy you are paying for in dx9 cards, and they have continued to do so.
Anonymous User - Thursday, October 23, 2003 - link
Once again "IQ to come in part 2"... mebbe they will ... mebbe they won't... but they don't have a very good track record so far... and what is up with that choice of games? Go read the [H]OCP review... I may have been vocal against [H] in the past but there review of teh 5700 and 5950 is spot on with worthwhile gaming results.....I really fail to see how you recommend 5700 over 9600pro in this.... and skip all the NV 'driver bugs' too.... ah well nm... another nail in the AT coffin....
Anonymous User - Thursday, October 23, 2003 - link
Hrmm, I see an NVida add on the top right of my screen. Ever see ATI adds ant anandtech? Know what complementary copy is?Anonymous User - Thursday, October 23, 2003 - link
Here's my conclusion: if you're gonna bitch and moan, read a different tech site. No one's forcing you to accept Derek's conclusions.I think some of you need to be a little more respectful with your comments and suggestions.
Anonymous User - Thursday, October 23, 2003 - link
How can any conclusions be made without an image quality comparison. The "final words" section is based purely on the framerate numbers? How can you even draw a conclusion?Anonymous User - Thursday, October 23, 2003 - link
I'll just copy this from what I wrote at Beyond 3D:I was so confused by this comment from AT:
AnandTech wrote: "In fact, NVIDIA has flipped the tables on ATI in the midrange segment and takes the performance crown with a late round TKO. It was a hard fought battle with many ties, but in the games where the NV36 based card took the performance lead, it lead with the style of a higher end card."
That I tabulated my own results:
NON AA
---------
5700 wins 10 times
9600 XT wins 6
Where the 5700 won, it won on average by 15%
Where the 9600 won, it won on average by 17%
WITH AA / ANISO
---------
5700 wins 6 times
9600 wins 6 times
Where the 5700 won, it won on average by 23%
Where the 9600 won, it won on average by 54%
There certainly is ZERO justification for saying something like: "but in the games where the NV36 based card took the performance lead, it lead with the style of a higher end card."
That characteristic belongs to ATI, not nVidia.
Another way to look at it: What percentage FPS difference is required to declare a "clear winner?"
Let's say that less than 10% difference, the cards are tied. In this case:
NO AA/ANISO
----------------
5700 wins 6 tests
9600 wins 4 tests
When the 5700 wins, it's by an average of 22%
When the 9600 wins, it's by an average of 22%
With AA/Aniso
----------------
5700 wins 4 tests
9600 wins 6 tests
When the 5700 wins, it's by an average of 33%
When the 9600 wins, it's by an average of 54%
I wish Anand's conclusions would actually agree with his data.
Anonymous User - Thursday, October 23, 2003 - link
Hello? where are the hardware, software, and driver specs? Editorial review? What's that?Anonymous User - Thursday, October 23, 2003 - link
Separating Image Quality results from the review is completely misleading.Anonymous User - Thursday, October 23, 2003 - link
It's not unplayable image quality errors - the pics in the hardocp review show missing graphical features to enhance your gaming - ie walls with computers on them with nvidia with no blinking lights, on the ati it had purple and green blinking lights - yes playable on both - but when you pay $499 you want to see the game the way it was intended by the programmers. Same goes for the flashlight pics on hardocp , nvidia the flashlight beam is a mess, ati the flashlight beam is perfectly round like a real flashlight.Just another case of nvidia removing graphical effects to speed up their cards to compete with ati.
DerekWilson - Thursday, October 23, 2003 - link
so, the cheapest 9800 Pro I see on new egg is a refurb for 280...also, there were no glaringly unplayable image quality issues on either side of the line.
give us a chance to get everything we want to get done done wrt image quality. We've got a lot planned.