Asus GTX 780 3GB DirectCU II OC Review
At the corner of the card, we find the unadvertised inclusion of “VGA Hotwire” points which can be used in tandem with select ROG motherboards to monitor and manually adjust core/memory/pll voltage values. Asus steadfastly refused to give us instructions on how to operate the feature (presumably due to Nvidia’s Green Light draconian controls and the fact that over-volting will shorten the lifespan of the card considerably and void the warranty).
On to the cooling department, Asus makes use of two 10cm fans (one of them with a custom fan blade design) to force air through a dense array of fins that are connected to the GPU core via a couple of thick 10mm copper heatpipes. The company claims 40% better heat transfer efficiency and 2.2x larger surface area for heat dissipation with their custom design over the stock cooler.
With the heatsink removed (just four screws around the GPU), we get to see the naked card in its full glory.
Here, surrounded by twelve 256MB Samsung 1.5Ghz GDDR5 memory modules, is the big GK110 ASIC that is manufactured with TSMC’s 28nm HKMG process. The card that we are reviewing here today comes with a very conservative factory overclock of 26MHz on the core.
A quick refresher – the GK110 used in the GTX 780 is a stripped down version from the one found on the Geforce Titan/Tesla K20X, with two SMX units disabled and double precision FP64 support artificially crippled. Memory bandwidth and ROP count remain untouched, so in reality the GTX 780 actually isn’t too far behind the Geforce Titan in real-world gaming performance.
Asus reworked the entire electrical subsystem, replacing the anemic analog solution on the stock GTX 780 to a beefier 8+2 phase digital VRM subsystem augmented by alloy chokes, resulting in a more stable/precise current and higher output for overclocking.