Question Why is the GTX 970 so much faster than the GTX 770?

[Sam K.]

Hello! I'm quarantined in my home and trying to figure out various different GPU specs and their impact on real world performance; as I don't have anything better to do at the moment!

Anyhow, I hit a wall while comparing GTX 770 with GTX 970 and need your opinions on the matter.

First, look at the screenshot below. As you can see, both GTX770 and 970 are running at the same core (1,215MHz) and memory frequencies (3,506MHz) and have the same 256-Bit bandwidth, which eliminates any bandwidth related variables. So far so good.

Since we know that the GTX770 has 1536 cores whereas the 970 has 1664, it's easy enough to calculate theoretical GFlop performance of both GPUs at this 'exact' moment:

GTX970: 0.002 x 1,215MHz x 1,664 cores = 4,043 GFlops.
GTX770: 0.002 x 1,215MHz x 1,536 cores = 3,732 GFlops.

As you can see, the GTX770 is just ~8% slower than the GTX970, or at least it should be, yet the frame rate suggests that the 770 is actually ~43% slower!

My question is a simple 'why'? Why the huge difference? What am I missing here? They should perform within ~10% margin because they've the exact same memory bandwidth and frequency and yet...

It's just super confusing!

So, any ideas?

 

[Spjut]

Nvidia has historically had longer driver support for their GPUs, roughly 10 years for both their DX9 and DX10 GPUs, compared to AMD's short support in the past.

To Nvidia's defense, they have actually updated Kepler to support new DX12 features like Shader Model 6.4, as well as Vulkan 1.2. But it doesn't seem to get game specific driver optimizations anymore, or perhaps its the studios themselves that won't bother adding separate paths to get performance up to speed on seven year old GPUs, unless Nvidia steps in.
Maxwell for that matter isn't performing well either in DOOM.

This has also been talked of before but AMD probably does get somewhat of a free ride from all engines being GCN-centric due to consoles. Which is also why I'm betting on the RDNA2+ lineup for my next build.