Well aren't all video cards limited by the core?
In fact, I can't even imagine a video card existing that isn't completely dependent on core. The memory bandwidth is merely to support the cores processing power right?
Yes, almost all cards are limited by the core to some degree, but its not always the primary limitation. A GF2 MX for example would have memory as the primary limitation by far.
Yes, but isn't a ~8% decrease (in performance) from the memory underclock quite significant when an equivalent decrease in core only yields a 11% decrease in performance?
Yes, but remember the whole internet was convinced the 5770 was primarily bottlenecked by its memory. If that was the case then reducing it shouldve dropped performance the most, but it didnt; performance dropped more when the core was underlocked.
So yes, youre quite right, 11.20% (core) vs 8.46% is very close, but it proves two things:
(1) The
core is primary limitation, not the memory.
(2) The 5770 is actually quite a balanced card and has been equipped with the right amount of bandwidth relative to its processing power.
As a comparison, on the 8800 Ultra I observed 12.64% core vs 5.45% memory overall. The 8800 Ultras results are even more different considering I ran half of the benchmarks without AA, while the 5770 didnt run anything lower than 2xAA.
If the 5770 was primarily bandwidth limited I wouldve expected similar numbers but reversed, except that didnt happen. So everyone running around claiming the 5770s performance is held back by its memory is technically correct, but performance is held back more by the core. I actually think the bottleneck is at the driver level personally, and not related to the hardware.
So yes, video cards will always be bottlenecked somewhere, but there are different degrees within each GPU element. Also if all clocks show similar performance drops then that means the part is balanced, and doesnt have an obvious limitation in one key area.
P.S. Thanks for doing this review. I was always interested in seeing underclocking results on the memory (considering the new GDDR5 or maybe its the controller has some type of error correction process that obscures results of the memory overclock)
Yes, Im glad someone gets it! Some people are confused why I underclock the parts instead of overclocking them, but what they dont realize is that its just a clock speed that offers a certain level of performance, and the hardware doesnt care about the English terms over and under that we apply to it.
The GDDR5 error correction is but one of many reasons why I believe its better to lower clocks than raise them. Other reasons include almost complete freedom with clocks (good luck getting 20%-30% overclocks on any GPU), and that fact that overclocking the GPU can skew the results if it starts exposing limitations in the CPU/platform.
IMO its much more reliable to start with a certain level of performance and then see what we lose when we reduce individual areas, because the stock clocks tell us what performance were supposed to get.