Originally Posted by gamervivek
Considering 32ROPs of Ellsmere are matching 64 on Hawaii, this bodes fairly well for Vega unless of course the bottleneck was elsewhere.
Since they are near doubling shader count again, they are going to run into similar bottlenecks again with Vega, if vega only gets 64 ROPs.
It would have been better if Polaris started with 64 ROPs while Vega got 128.
Originally Posted by epic1337
why don't you compare the buswidth and bandwidth between the two uarch?
280X (Tahiti) = 2048:128:32 | 384bit @ 288GB/s = 100% perf
380X (Tonga) = 2048:128:32 | 256bit @ 182.4GB/s = 100% perf
480 (Polaris) = 2304:144:32 | 256bit @ 256GB/s = ~110% perf
you see the thing here? Tonga has much less buswidth, yet performs roughly the same as Tahiti.
this is because of multiple design changes, one is the introduction of compression, the other is ROP optimizations.
you're being too much biased in raw CU throughput and forgot that the front-end also needs optimizations.
with optimizations on the front-end, they can fit more CUs and thus increase card perf without dramatically increasing die-size.
If we going to fawn over those improvements, what are we going to say about pascal? It has 50% increase of the performance over the rx 480 with the same bandwidth of polaris. And this is with 25% of it's shader's disabled.
The problem with being marveled by these accomplishment is that Tonga actually didn't shrink the die down or decrease the number of transistors vs Tahiti/hawaii. Tonga is actually a bit bigger and has 20% more transistors than tahiti but has performance maybe 5% better overall. I would be more impressed if the changes in Tonga and similarly Polaris(not changes due to change in node) decreased the transistor count for the same performance or increased the performance per transistor or performance per mm2 of die. This is what happened between the transition between kepler and maxwell and maxwell vs pascal. And this is what AMD needs to do to catch up.
Why AMD has been letting so many people down is for their changes to GCN, they are not increasing the performance per transistor or die size. This comes with good architectural changes. If their changes were actually doing things which increased the IPC, for the number of transistors the rx480 has, it should be 20% faster than it is. Hawaii has double precision which occupy alot of transistors, is 28nm and has better overall performance than the rx480 for 9% percent more transistors.
All these changes are just not getting the job done. For a pure gaming part with no double precision, unlike hawaii, on a superior node, 5.7 billions transistors of Polaris should outperform 6.2 billion hawaii transistors.
Pascal was able to beat the titan X by 30% using 10% less transistors.
RX480 loses to the 390x by 10% while giving double precision the boot while using 9% less transistors, and they were the ones that made the bigger architectural changes.
This is the most disappointing things. AMD should have gained more for the architectural changes.
What we have is AMD shuffling around it's transistor to beef some things up while making some things weaker which for all their changes = the same performance. That is a waste of R and D. What we need from GCN, if they are to keep on using it, are changes that result in overall increases in performance across the board, not weakening in some area while others increase so the overall performance is the same.
We have known for the 232mm2 part for a while now but when you take the lowest performance expectation that anyone was expecting on this forum and combine it with a worse power consumption than anyone could have predicted, you have mostly disappointing feeling towards polaris as an architecture. Anyone saying anything else is lowering their bar for their favorite company.Edited by tajoh111 - 7/7/16 at 11:52pm