ASUS HD 7790 DirectCU II 1GB (HD7790-DC2OC-1GD5)
ASUS offers two Radeon HD 7790s differing only in the amount of onboard memory. We’ve got the HD7790-DC2OC-1GD5 model which is equipped with 1 gigabyte of it. The card is shipped in a compact box that’s covered with descriptions of product features:
Besides the graphics card, the box contains a CrossFireX bridge, a DVI->D-Sub adapter, a CD with drivers and ASUS GPU Tweak utility, and a brief installation guide.
The product is manufactured in China and comes with a 3-year warranty. Its minimum retail price is $150.
The ASUS HD 7790 DirectCU II is rather compact. It is only 216 mm long, and even this length is due to the oversized DirectCU II cooler:
Besides a standard set of video connectors (dual-link DVI-I and DVI-D, HDMI 1.4a and DisplayPort 1.2), there is a vent grid in the card’s mounting bracket to exhaust the hot air out of the computer case.
The card has one MIO connector for building CrossFireX tandems and a 6-pin power connector.
Its power draw is specified to be no higher than 85 watts in 3D applications. A 500-watt PSU is recommended for a computer with one Radeon HD 7790 inside.
The ASUS HD 7790 DirectCU II has the reference PCB design with 5-phase power system.
The power system is governed by an ON Semiconductor NCP81022 controller which doesn’t support software-based voltage management.
The GPU lacks a protective frame, so you have to be extremely cautious when removing or installing the cooling system.
The GPU die was manufactured on the 6th week of 2013 in Taiwan. It is pre-overclocked by 75 MHz (+7.5%) compared to the reference Radeon HD 7790, so its clock rate in 3D applications is 1075 MHz. In 2D applications the GPU frequency is lowered to 300 MHz. The ASIC quality of the chip is 66.3%:
The card carries four FCBGA-packaged chips for a total of 1 GB of GDDR5 memory. These are H5GQ2H24AFR R0C chips from Hynix Semiconductor:
Rated for 6000 MHz, the memory chips are clocked at 6400 MHz on the ASUS card. In 2D mode the frequency is lowered to 600 MHz. The memory bus is 128 bits wide, so the peak bandwidth is 102.4 GB/s, which is 6.7% higher than the reference card’s.
The DirectCU II cooler is in direct contact with the GPU whereas the power components lack any heatsink and are only cooled by the air flow from the fans.
The cooler consists of an aluminum heatsink with two 6mm heat pipes and thin aluminum fins. It has a plastic casing with two 75mm fans.
The speed of the fans is PWM-regulated in a range of 1100 to 3500 RPM. Here’s a picture of the direct-touch technology implemented in the ASUS DirectCU II cooler:
Hereinafter, to check out the cards temperatures we used five runs of the pretty resource-hungry Aliens vs. Predator (2010) benchmark at the highest visual quality settings, at a resolution of 2560x1440 pixels. We used 16x anisotropic filtering but no MSAA 4x, because this load would be too much for the video memory on these graphics cards to handle, and the GPU wouldn’t heat up as much as we needed it to.
We used MSI Afterburner 3.0.0 beta 10 and GPU-Z version 0.7.1-0.7.2 for monitoring of temperatures inside the closed system case, which configuration is discussed in detail in the corresponding chapter of the roundup. All tests were performed at 27-28°C room temperature.
When the fans were regulated automatically and reached a speed of 1790 RPM, the GPU was only 64°C hot.
Auto fan mode
Maximum fan speed
At the maximum speed of the fans (3430 RPM), the GPU temperature went down to 57°C, so ASUS’s exclusive DirectCU II cooler proved its high efficiency once again.
As for the overclocking potential of the ASUS HD 7790 DirectCU II, we could increase its GPU clock rate by 145 MHz. The memory chips could only be overclocked by 240 MHz:
Thus, the overclocked card worked at 1220/6640 MHz.
The overclocked ASUS HD 7790 DirectCU II had a GPU temperature of 65°C at 1900 RPM.