To overclock our trio of contenders, we used the latest versions of the respective overclocking tools that each one produces: ASUS GPU Tweak, EVGA Precision X 16 and MSI Afterburner. The following table shows the highest stable overclocked settings we were able to achieve with each card.
ASUS Strix GTX 970 DirectCU II OC
EVGA GTX 970 SC ACX2
MSI GTX 970 Gaming 4G
Factory Settings
Base clock
1,114MHz
1,165MHz
1,140MHz
Boost clock
1,253MHz
1,317MHz
1,279MHz
Memory clock
1.75GHz (7GHz effective)
1.75GHz (7GHz effective)
1.75GHz (7GHz effective)
Maximum Overclocked Settings
Base clock
1,279MHz
1,290MHz
1,315MHz
Rated boost clock
1,418MHz
1,442MHz
1,454MHz
Observed boost clock
~1,430MHz
~1,430MHz
~1,504MHz
Memory clock
1.95GHz (7.8GHz effective)
1.925GHz (7.7GHz effective)
1.95GHz (7.8GHz effective)
Base clock increase
165MHz (14.8%)
125MHz (10.7%)
175MHz (15.4%)
Memory clock increase
800MHz effective (11.4%)
700MHz effective (10%)
800MHz effective (11.4%)
Other Settings
Power limit
120%
110%
110%
Temperature limit
91°C
91°C
91°C
GPU voltage increase
87mV
37mV
50mV
Fan speed
Manual (50%)
Auto
Auto
As you can see, the best overclocker is the MSI GTX 970 Gaming 4G, as it reaches the highest base clock and the joint highest memory clock. It's the only card to reach a base clock greater than 1,300Mhz, which is just insane for a GPU. Even crazier is the fact that it was happy to boost to a constant 1.5GHz! Such frequencies are almost unheard of for graphics cards, especially for bog standard air cooled ones with no voltage modifications. The combination of Maxwell's efficiency and MSI's hefty power delivery system clearly serves it well.
However, that's not to say that the ASUS or EVGA cards are slouches when it comes to overclocking. We were able to increase the ASUS base frequency by 15 percent. However, the higher original base clock of the EVGA GTX 970 SC ACX2 meant that an 11 percent increase here was enough to surpass by the ASUS card. However, in practice the two perform almost identically, as both were boosting to around 1,430MHz under load. The ASUS Strix card has a minor advantage on memory frequency too, as it's able to match the MSI's effective frequency of 7.8GHz whereas the EVGA edition only hits 7.7GHz – this is most likely due to the luck of the drawer.
One issue we did notice with the ASUS card is that it initially wasn't boosting as high as we'd have expected. We noticed that the fans didn't seem to want to spin beyond 42 percent, apparently prioritising low noise over boost frequency. As such, we set the fans manually to 50 percent, which saw a higher and more constant boost clock emerge. The downside to this is that the fan speed is locked, and won't slow down or enter its passive mode, even when idle.
Overclocking - Battlefield 4
2,560 x 1,440, DirectX 11, 'Ultra' Settings
AMD Radeon R9 295X2 8GB
Nvidia GeForce GTX Titan Black 6GB
MSI GTX 970 Gaming 4G 4GB (OC)
Nvidia GeForce GTX 780 Ti 3GB
Nvidia GeForce GTX 980 4GB
ASUS Strix GTX 970 DirectCU II OC 4GB (OC)
EVGA GTX 970 SC ACX2 4GB (OC)
AMD Radeon R9 290X 4GB
EVGA GTX 970 SC ACX2 4GB
MSI GTX 970 Gaming 4G 4GB
ASUS Strix GTX 970 DirectCU II OC 4GB
Nvidia GeForce GTX 780 3GB
AMD Radeon R9 290 4GB
75
91
44
54
43
56
43
54
42
57
42
55
42
55
40
48
39
50
38
50
38
49
38
46
37
45
0
25
50
75
100
Frames Per Second
Minimum
Average
Overclocking - Crysis 3
2,560 x 1,440, 0x AA, 16x AF, 'Very High' Settings