I made the request and was granted the option of creating this thread about architectural differences in the current GPUs which will be heavily moderated- I am very interested in discussion about the different approaches and how they are playing out and will play out and think we should be able to handle this without the loyalists comments that come in to play.
To get it out of the way up front from an overall architectural standpoint from everything I have been able to gather on a computational level the GF100 has a rather clear advantage over the 58xx parts- but it *should* considering its' significant size and power requirement differences. I'm stating this up front so people don't try and talk about a slanted angle, all that extra die space, power and heat really are there for a reason, it just isn't going to show up in current games.
With the disclaimers out of the way....
First up, fillrate. The 58xx parts have a massive advantage on this front and it makes itself clearly visible in current games when pushed to the highest resolutions. This is a fairly simple and straightforward observation but looking into it a bit more it is the first time that a company has released a new top end part that has considerably less texel fillrate then the previous generation. Even the 57xx parts are competitive to the GF100 here, obviously a very distinct divergence has taken place in terms of design philosophy. While we have known for a while that the general direction of games has been changing the ratio of raw fill/shader ops in the direction of shaders, this is the first time we have seen a company release a part that went to the extreme of actually reducing what was for a long time the defining raw metric used to define vid cards, texel fill. Old timers will likely recall the old 'fillrate is king' mantra, and while that obviously died off some time ago, the thought never even dawned on me that we would head backwards in that area.
To me that indicates a bet on the direction that games will be taking. Heavy useage of elements that chew up raw fill are going to choke, badly, on the GF100 based parts when compared to their 58xx counterparts. Nothing nVidia does with driver updates or anything else is going to fix that. They have a brick wall they are going to run into, there is no getting around it. *IF* games start to take on a direction where they are far more reliant on shader ops then raw fill tactics, this choice could look very smart in retrospect. If we stay our current course, it won't end up looking to great for nV. They need the current trend to have a sharp spike in it for it to pay any sort of appreciable dividends.
Up next tesselation. Clearly, nVidia dominates this area. ATi has had tesselation for a long time now, old timers will likely recall TruForm doing some interesting things with CounterStrike back in the days when it was running on Carmack's engine. I think that we had a bit of two elements ending up with the huge disparity in tesselation performance. One, ATi likely thought that with their extensive time and experience having a tesselation engine, they were going to have a superior offering to nV who was too tied up with compute logic. I would have made that same judgement myself. nV probably thought that ATi was going to try and push tesselation hard and wanted to go over the top and try to take their trump card out from under them. In the end, from a consumer point of view, I think the advantage here ends up in ATi's favor because nV's tesselation advantage is so strong that nV blew a lot of transistors on something developers won't be able to use or else they will make it unplayable on anything but a GF100 based part(we may see a few outliers like we do today with PhysX).
General shader hardware- in terms of raw throughput, the parts are quite close. In implementation everyone should be aware that nV devoted a lot more effort to this area, largely due to them making use of it for other purposes. For gaming uses the biggest advantage I see for nV is that they are more likely to handle *any* shader code at reasonable speed. Their entire layout seems very friendly for less then optimal code, this is another tradeoff. To compare it to CPUs a general way of looking at it is ATi is kind of like Cell, extremely potend with the right kind of code, but severe performance penalty for less then optimal useage. nV is more along the lines of x86, never going to hit the same peak throughput, but going to handle anything you throw at it with reasonable speed(those are very loose comparisons, just trying to give a general idea). This is likely going to play well for nV in terms of getting better performance on the newest titles out of the box, less driver optimizations in terms of compiler tweaks etc. Conversely, ATi should have the biggest improvements with driver updates for titles throughout the life of their current parts.
GPGPU- Obviously, utter domination by nVidia. I know most people here don't care, I do quite a bit of video transcoding and there are going to be a lot of CS5 users who find it to be a pretty big deal. A lot of peak throughput numbers get thrown around about how the parts are fairly close, in actual useage it looks like the 480 should be close to twice as fast as the 5870 in bad cases for the 480, somewhere in the 600%-1000% faster in situations better suited for it. A hefty amount of the extra transistors they are carrying is because of this, their layout and the way on chip communication is handled is *far* more CPU like then any GPU we have seen to date. The cache structure and the ability of the different segments of the chip to communicate with each other along with lots of other refinements truly have this on an entriely different level. I don't consider this a slight to ATi at all, they made a choice not to compete in this segment, and in doing so they ended up with a smaller, cooler, earlier chip. Be that as it may, anyone who wants to do anything GPGPU related really has only one viable choice at the moment in the high end segment.
On this same topic, some of the new functionality of the GPGPU elements of this chip actually could be used in games, hardware recursion is an interesting one as it makes ray tracing a realistic possibility in terms of added effects moving forward(not full ray tracing, but hybrid to generate very high quality reflections). These types of features are something that again won't show up in games anywhere close to the near future, but are very interesting from a design perspective as where they are leading us to.
This generation is the first major shift away from each other I have seen ATi and nV take in terms of architectural direction. Not talking about strictly die size, but the overall ratio of what they are spending transistors on. For nV to reduce their raw fill while pushing an exponential increase in geometric throughput as a general example, it is a very interesting design choice. Perhaps we are seeing nV do what ATi is going to do with their next major redesign, or perhaps this is the general direction both companies are headed in.
I've said it many times and I do firmly believe it, most games today are simply ports of console titles. On that particular front, I see the 58xx parts having a clear architectural advantage over nV. That isn't to say they will always be faster, but in terms of die space/performance they should obliterate nV. Moving forward, if we have games that start making use of heavy tesselation or, and I find this *highly* unlikely, we have games using ray tracing as a post process type of effect for reflections, it is likely that nV will destroy the 58xx parts, badly(although, this would almost certainly end up akin to PhysX, the performance rift would be so severe that people wouldn't compare the parts at all with the features on).
With ATi belonging to AMD, I'm not sure that ATi is going to be interested in heading down the same path that nV is at all. Not saying that they won't, but if they can avoid GPGPU ever taking off, it helps their CPU division while hurting one of their major competitors. Of course, they have the desireable position of also being able to adapt rather quickly and respond if consumer demand starts showing an increased interest level. I would imagine that they would like to at least increase their presence in the segment before Intel fixes the mess that is Larrabee and manages to get something workable out of the design, but that could be years from now.
Clearly looking long term, we are nearing the point of being completely fill 'complete', although nV backed off before that became a 'wall'. They also have placed considerable amounts of resources into elements that may or may not be utilized by the masses at all. Their part is clearly the more risky design, the hotter design, and the larger design. If ATi feels any pressure from nV on the performance front, looking at it from an overall design standpoint, they should be able to reduce an upclocked part that can best the 480 relatively speaking easily. Actually, in terms of overall gaming performance as it stands now, it seems that any part that nV could release on this build process ATi should be able to beat it if they are so inclined(a "simple" respin still costs millions, so keep in mind that is a business decission that does have drawbacks to a company trying to make money). If games start shipping that make use of all the extra transistors that nV has packed its' parts with, ATi simply doesn't stand a chance with their current offerings.
Serious discussion only. Folks who troll, bait, provoke, cr@p or otherwise disrupt this thread will be punted. Thanks in advance.
Anandtech Moderator - Keysplayr
To get it out of the way up front from an overall architectural standpoint from everything I have been able to gather on a computational level the GF100 has a rather clear advantage over the 58xx parts- but it *should* considering its' significant size and power requirement differences. I'm stating this up front so people don't try and talk about a slanted angle, all that extra die space, power and heat really are there for a reason, it just isn't going to show up in current games.
With the disclaimers out of the way....
First up, fillrate. The 58xx parts have a massive advantage on this front and it makes itself clearly visible in current games when pushed to the highest resolutions. This is a fairly simple and straightforward observation but looking into it a bit more it is the first time that a company has released a new top end part that has considerably less texel fillrate then the previous generation. Even the 57xx parts are competitive to the GF100 here, obviously a very distinct divergence has taken place in terms of design philosophy. While we have known for a while that the general direction of games has been changing the ratio of raw fill/shader ops in the direction of shaders, this is the first time we have seen a company release a part that went to the extreme of actually reducing what was for a long time the defining raw metric used to define vid cards, texel fill. Old timers will likely recall the old 'fillrate is king' mantra, and while that obviously died off some time ago, the thought never even dawned on me that we would head backwards in that area.
To me that indicates a bet on the direction that games will be taking. Heavy useage of elements that chew up raw fill are going to choke, badly, on the GF100 based parts when compared to their 58xx counterparts. Nothing nVidia does with driver updates or anything else is going to fix that. They have a brick wall they are going to run into, there is no getting around it. *IF* games start to take on a direction where they are far more reliant on shader ops then raw fill tactics, this choice could look very smart in retrospect. If we stay our current course, it won't end up looking to great for nV. They need the current trend to have a sharp spike in it for it to pay any sort of appreciable dividends.
Up next tesselation. Clearly, nVidia dominates this area. ATi has had tesselation for a long time now, old timers will likely recall TruForm doing some interesting things with CounterStrike back in the days when it was running on Carmack's engine. I think that we had a bit of two elements ending up with the huge disparity in tesselation performance. One, ATi likely thought that with their extensive time and experience having a tesselation engine, they were going to have a superior offering to nV who was too tied up with compute logic. I would have made that same judgement myself. nV probably thought that ATi was going to try and push tesselation hard and wanted to go over the top and try to take their trump card out from under them. In the end, from a consumer point of view, I think the advantage here ends up in ATi's favor because nV's tesselation advantage is so strong that nV blew a lot of transistors on something developers won't be able to use or else they will make it unplayable on anything but a GF100 based part(we may see a few outliers like we do today with PhysX).
General shader hardware- in terms of raw throughput, the parts are quite close. In implementation everyone should be aware that nV devoted a lot more effort to this area, largely due to them making use of it for other purposes. For gaming uses the biggest advantage I see for nV is that they are more likely to handle *any* shader code at reasonable speed. Their entire layout seems very friendly for less then optimal code, this is another tradeoff. To compare it to CPUs a general way of looking at it is ATi is kind of like Cell, extremely potend with the right kind of code, but severe performance penalty for less then optimal useage. nV is more along the lines of x86, never going to hit the same peak throughput, but going to handle anything you throw at it with reasonable speed(those are very loose comparisons, just trying to give a general idea). This is likely going to play well for nV in terms of getting better performance on the newest titles out of the box, less driver optimizations in terms of compiler tweaks etc. Conversely, ATi should have the biggest improvements with driver updates for titles throughout the life of their current parts.
GPGPU- Obviously, utter domination by nVidia. I know most people here don't care, I do quite a bit of video transcoding and there are going to be a lot of CS5 users who find it to be a pretty big deal. A lot of peak throughput numbers get thrown around about how the parts are fairly close, in actual useage it looks like the 480 should be close to twice as fast as the 5870 in bad cases for the 480, somewhere in the 600%-1000% faster in situations better suited for it. A hefty amount of the extra transistors they are carrying is because of this, their layout and the way on chip communication is handled is *far* more CPU like then any GPU we have seen to date. The cache structure and the ability of the different segments of the chip to communicate with each other along with lots of other refinements truly have this on an entriely different level. I don't consider this a slight to ATi at all, they made a choice not to compete in this segment, and in doing so they ended up with a smaller, cooler, earlier chip. Be that as it may, anyone who wants to do anything GPGPU related really has only one viable choice at the moment in the high end segment.
On this same topic, some of the new functionality of the GPGPU elements of this chip actually could be used in games, hardware recursion is an interesting one as it makes ray tracing a realistic possibility in terms of added effects moving forward(not full ray tracing, but hybrid to generate very high quality reflections). These types of features are something that again won't show up in games anywhere close to the near future, but are very interesting from a design perspective as where they are leading us to.
This generation is the first major shift away from each other I have seen ATi and nV take in terms of architectural direction. Not talking about strictly die size, but the overall ratio of what they are spending transistors on. For nV to reduce their raw fill while pushing an exponential increase in geometric throughput as a general example, it is a very interesting design choice. Perhaps we are seeing nV do what ATi is going to do with their next major redesign, or perhaps this is the general direction both companies are headed in.
I've said it many times and I do firmly believe it, most games today are simply ports of console titles. On that particular front, I see the 58xx parts having a clear architectural advantage over nV. That isn't to say they will always be faster, but in terms of die space/performance they should obliterate nV. Moving forward, if we have games that start making use of heavy tesselation or, and I find this *highly* unlikely, we have games using ray tracing as a post process type of effect for reflections, it is likely that nV will destroy the 58xx parts, badly(although, this would almost certainly end up akin to PhysX, the performance rift would be so severe that people wouldn't compare the parts at all with the features on).
With ATi belonging to AMD, I'm not sure that ATi is going to be interested in heading down the same path that nV is at all. Not saying that they won't, but if they can avoid GPGPU ever taking off, it helps their CPU division while hurting one of their major competitors. Of course, they have the desireable position of also being able to adapt rather quickly and respond if consumer demand starts showing an increased interest level. I would imagine that they would like to at least increase their presence in the segment before Intel fixes the mess that is Larrabee and manages to get something workable out of the design, but that could be years from now.
Clearly looking long term, we are nearing the point of being completely fill 'complete', although nV backed off before that became a 'wall'. They also have placed considerable amounts of resources into elements that may or may not be utilized by the masses at all. Their part is clearly the more risky design, the hotter design, and the larger design. If ATi feels any pressure from nV on the performance front, looking at it from an overall design standpoint, they should be able to reduce an upclocked part that can best the 480 relatively speaking easily. Actually, in terms of overall gaming performance as it stands now, it seems that any part that nV could release on this build process ATi should be able to beat it if they are so inclined(a "simple" respin still costs millions, so keep in mind that is a business decission that does have drawbacks to a company trying to make money). If games start shipping that make use of all the extra transistors that nV has packed its' parts with, ATi simply doesn't stand a chance with their current offerings.
Serious discussion only. Folks who troll, bait, provoke, cr@p or otherwise disrupt this thread will be punted. Thanks in advance.
Anandtech Moderator - Keysplayr
Last edited by a moderator:
. It's going to be a great year.
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