All of our benchmarks are run with a stock GTX 980 and with stock GTX 980 SLI. We test our Ivy Bridge Core i7-3770K at stock (3.5GHz/3.7GHz) and also overclocked to 4.6GHz in our EVGA Z77 FTW (x16+x16 PCIe 3.0) motherboard. Likewise, the 4770K is tested at stock and overclocked in our ECS Z87 motherboard while Devil’s Canyon i7-4790K is tested in the ECS Z87 and (since it didn’t overclock in the ECS MB) also in the ASUS Z97-E motherboard.
We are going to start out with our Big Picture first. And since there is so much information available in one place, it might prove confusing, so we will break it down into smaller charts also.
Here is all of our testing in one place – we call it, “The Big Picture”. All games have their setting completely maxed out and levels of AA are identified on the chart. The GTX 980 nd GTX 980 SLI are run at reference clock speeds. Z77 refers to the i7-3770K exclusively as benchmarked in the EVGA Z77 FTW motherboard at stock clocks and also overclocked to 4.5GHz. Z87 refers to the ECS Z87 Golden Motherboard used to test both the stock and overclocked i7-4770K and 4970K; and Z97 refers to the ASUS Z97-E motherboard also used to test both the stock and overclocked i7-4770K and 4970K.
The chart is labeled first to differentiate the GTX 980 from GTX 980 SLI and then further subdivided by CPU speed, stock and overclocked; and by motherboard, Z77 for i7-3770K and Z87 (ECS) and Z97 (ASUS) for i7-4770K and 4790K. Stock speeds are expressed as base clocks/turbo clocks and overclocked speeds have all 4 cores synced. The ASUS motherboard generally syncs all 4 cores to 4.4GHz with a single tweak, while the ECS motherboard manages to reach 4.2GHz.
The Big Picture
Let’s break it down. First, let’s look at the differences between motherboards. And let’s limit ourselves to GTX 980 single GPU results first. For these series of tests we used i7-4770K and 4790K at stock and overclocked, in the Z87 ECS motherboard and also in the ASUS motherboard. At stock settings, the ASUS mother board will sync and turbo all 4 cores to 4.4GHz if any tweaks are made, even under load. On the other hand, the ECS motherboard usually turbos two cores to 4.4GHz, one to 4.3GHz and the other core to 4.2GHz; but usually all four cores to 4.2GHz under load.
Single GTX 980 results
Now let’s focus just on GTX 980 SLI scaling:
GTX 980 SLI Scaling
Finally, let’s put some relevant information in the charts next to each other in a variation of the Big Picture.
The Last Chart
We see good overall scaling related to CPU core speeds and much more differentiation at 1920×1080 than at 2560×1600. The GTX 980 is sufficient to differentiate between CPU speeds and GTX 980 SLI much more so. Some games are very GPU dependent and vary little whereas others are somewhat CPU-limited.
If you are a gamer, you can definitely get by with an older CPU, such as a highly overclocked Bloomfield Core i7-920. However, we saw the need to upgrade to Haswell and to Ivy Bridge more strongly indicated by many tasks other than gaming, not to mention efficiency, which we did not explore in this evaluation. Let’s head for our conclusion.