Nvidia GeForce GTX 970 Review Roundup: feat. ASUS, EVGA and MSI

EVGA GeForce GTX 970 SC ACX2 4GB Review

Manufacturer: EVGA
UK price (as reviewed): £287.99 (inc VAT)
US price (as reviewed): Currently unavailable

Next on the agenda is the EVGA GTX 970 SC ACX2, which comes in at just under £290 and is thus the middle of the road card for price. The SC in the name refers to “SuperClocked”, and that's not an exaggeration; the base clock is set at 1,165MHz, giving it a boost clock of over 1,300MHz, or 1,317MHz to be precise. This is an 11 percent overclock – we've only seen two other GTX 970 cards on the market with higher speeds than this, and both are more expensive. However, like the other two cards here, the GTX 970 SC ACX2 ships with stock speed memory.


Bundled in the retail box is a large poster and some stickers, a DVI to VGA adaptor (let it die already!) and a pair of dual molex to 6-pin PCI-E power adaptors with lovely, individually braided cables.

Physically, the card is nice and constrained; it's just 241mm long and 111mm tall, thus fitting inside the standard PCI bracket measurements.


Connectivity is the same as we we on the other two cards: dual-link DVI-I, dual-link DVI-D, HDMI 2.0 and DisplayPort 1.2.

The GTX 970 SC ACX2 has a fairly understated look with a minimalist black plastic shroud with some small blue highlights. It has a more closed in design than the other two cards but the shroud is not fully sealed so hot air will still escape into your chassis, though some will also find its way out of the big holes in the rear I/O panel.


There is no backplate on our sample, and as such we find four of the eight memory chips exposed on the back of the PCB. However, EVGA has informed us that the lack of a backplate is due to the rushed production of the initial match to meet the launch and that future batches will come with a backplate. It also said that any European users that receive a card from the first batch can register it online to receive a free backplate – we recommend any buyers do take advantage of this for the extra stability, protection and cooling it will enable, especially given that there are four uncovered memory chips on the rear of the PCB.


The same 4Gb Samsung 7Gbps are used by EVGA as on the other other two cards (and the GTX 980). Whether Nvidia requires that these chips specifically be used with its GM204 GPU remains to be seen, but it certainly seems to be the norm. They overclocked pretty well on the GTX 980 – hopefully the same is true here.


The rear of the PCB also includes what looks like a dual BIOS switch (shown above), but it has been blocked out on our sample and is inaccessible. It could be reserved for RMA issues, or perhaps will be enabled in future revisions.

ACX 2.0 is a new cooling solution from EVGA that comprises a triple heat pipe heatsink and a pair of 85mm fans. The copper, U-shaped heat pipes are nickel plated and are designed to make direct contact with the GPU. However, as you can see from the thermal goo outline, only two actually touch the GPU, which will significantly reduce the effectiveness of the third one.

Update: EVGA has since released a statement in respose to concerns raised about the effectiveness of the ACX2 cooling solution:

The way the EVGA GTX 970 ACX heat sink was designed is based on the GTX 970 wattage plus an additional 40% cooling headroom on top of it. There are 3 heat pipes on the heatsink – 2 x 8mm major heat pipes to distribute the majority of the heat from the GPU to the heatsink, and a 3rd 6mm heatpipe is used as a supplement to the design to reduce another 2-3 degrees Celsius. Also we would like to mention that the cooler passed NVIDIA Greenlight specifications.

Due to the GPU small die size, we intended for the GPU to contact two major heat pipes with direct touch to make the best heat dissipation without any other material in between.

We all know the Maxwell GPU is an extremely power efficient GPU, our SC cooler was overbuilt for it and allowed us to provide cards with boost clocks at over 1300MHz. EVGA also has an “FTW” version for those users who want even higher clocks.

http://www.evga.com/images/forum/precision_gtx970sc.png

Regarding fan noise, we understand that some have expressed concerns over the fan noise on the EVGA GTX 970 cards, this is not a fan noise issue but it is more of an aggressive fan curve set by the default BIOS. The fan curve can be easily adjusted in EVGA PrecisionX or any other overclocking software. Regardless, we have heard the concerns and will provide a BIOS update to reduce the fan noise during idle.


The main feature of ACX 2.0 is its news fans, featuring double ball bearings, a new motor with improved, silicon steel magnets and redesigned internals. As a result of these changes, the motor requires less energy to spin and the maximum RPM is increased; EVGA claims its fans consume up to 250 percent less power than its competitors and that these power savings can be passed onto the GPU for more effective overclocking. Fan lifespan is also up by up to 400 percent thanks to the double ball bearing design. Finally, the redesigned “Swept” fan blades, which are angled away from the direction of rotation, reduce wind resistance and turbulence making them easier to spin and again more efficient. The new blade design, and the fact that EVGA now uses more blades (11), means the fans can pushed more air at lower noise levels.


One thing the ACX2 cooler does lack is a semi-passive mode. Even when idle, the fans will be spinning, which is not the case with the ASUS or MSI models. Both fans are also controlled by the same 4-pin header so there's no independent control.

EVGA sticks with the reference power input design, equipping the GTX 970 SC ACX2 with dual 6-pin power connectors.


Examining the PCB reveals a 4+2 phase power design – four phases near the rear I/O for the GPU, and two in the bottom right corner for the memory. This is a slight upgrade from the 4+1 stock specification but unlike MSI and ASUS, EVGA does not use any specially crafted components.


The GPU MOSFETs are directly cooled by the main heatsink, which has a thermal strip on to draw heat up into the fin stack. On the other side of the GPU is a metal contact plate that partially cools two of the four memory chips on this side, leaving the other two exposed. It also cools the MOSFETs of the power phases serving the memory, but no thermal pads are used, so heat transfer is likely to be limited.