Why isn't HD3870 beating up the 8800GT?

[darkxknight]

the HD3870 outclasses the 8800GT in pretty much every category. why does it perform slightly slower rather than much greater than the 8800GT?

HD3870
Core clock: 775MHz
Stream Processors: 320 stream processing units
Memory Clock: 2400MHz
Memory Size: 512MB GDDR4
Memory Interface: 256-bit

8800GT
Core clock: 670MHz
Stream Processors: 112
Memory Clock: 1950MHz
Memory Size: 512MB GDDR3
Memory Interface: 256-bit

is it the drivers or what?

 

[SickBeast]

The shader clock on the 8800GT is around 3X that of the 3870.

My guess is that the games aren't complex enough to utilize all 320 stream processors at once, leading to waste.

The DDR4 doesn't give all that much of a boost.

 

[MegaWorks]

We're talking about two different architecture here.

ATI stream is 64 scalar X 5 = 320 stream processing running at 775mhz

the G80 has 128 scalar stream processors running at 1.35GHz.

SickBeast is right most of the RV670 stream goes to waste. I also think that game developers have to adopt this architecture to fully use all of ATI's stream process.

 

[taltamir]

The AMD stream processors are not full stream processors... only one in X (i think one in 8) is a full stream process capable of doing floating point (decimal) calculations... the rest are limited SP...
Also their SP are running at the same clock as the core, about a third of the nvidia SP speed... seeing as most games are shader heavy thats a big difference...

AND there is the fact that the actual architecture is different. A faster GHz rating was never indicative of speed, EXCEPT when comparing the exact same chip... even minor revisions within a specific chip (ie, steppings) change the amount of performance per MHz...

 

[Pacfanweb]

Originally posted by: SickBeast

My guess is that the games aren't complex enough to utilize all 320 stream processors at once, leading to waste.

And if they were, everything else about the game would be complex, too, so it would bog the card down to unplayability. So you'd need everything else to be even faster than it already is.

And core clocks are irrelevant if the processors are more efficient....AMD hasn't come close to Intel in raw clock speed in years but until recently (relatively speaking) their processors have performed better.