PCB Design and Specifications
ASUS is one of the few graphics card makers that risk developing unique products with custom-made PCBs. The ENGTX580 DCII is but barely reminiscent of Nvidia’s reference design (on the right).
It is a truly monumental product as it takes as many as three slots in a system case. In fact, it is also desirable that a fourth slot be empty as well, so that the card’s cooling system could get the fresh air it needs. Compact system cases won’t do for this card because it is longer than the reference one. It is also incompatible with stiff SLI bridges. With the cooler removed, we can see the following:
The metallic back-plate, although equipped with a thermal pad, serves an aesthetic rather than a practical purpose. There is nothing to cool on the reverse side of the PCB because the power circuit elements are all on the face side. The only interesting thing we can spot here is the film capacitor NEC/Tokin 0E907. Notwithstanding its small size, it has a capacitance of 900 µF. ASUS suggests that this rare and expensive component is going to increase the overclocking potential of the ENGTX580 DCII. We’ll check this out shortly.
The face side of the PCB is a very exciting view because ASUS developers have left virtually nothing of Nvidia’s reference design. It is clear now why the card is so tall. The 10-phase power system wouldn’t fit onto an ordinary PCB with the given selection and layout of components. It’s somewhat odd that they used discrete components (power drivers and transistors) rather than integrated packs which would make the card smaller.
The power system employs high-quality capacitors and chokes that bear ASUS’s SAP logo. The SAP chokes have a solid core which eliminates the high-frequency noise of cheap ordinary chokes.
The graphics card’s power circuit features 8+2 design you can see on many top-end products. The GPU voltage regulator is based on a SHE ASP0907 chip. We saw it before on board the ASUS HD 6870 DirectCU and have reasons to think that it is a rebranded uP6208 or uP6225. The dual-phase memory voltage regulator is managed by an uP6223 controller.
Interestingly, the developers of this card have disabled overvoltage protection in order to give the user unlimited freedom to overclock. Although the large cooler should cope with any load you can throw at it, there is a higher risk of damaging a graphics card if it has no protection. You should keep this in mind when overclocking.
The ASUS ENGTX580 DirectCU II bears 12 GDDR5 memory chips from Samsung Semiconductor. These K4G10325FE-HC04 chips have a capacity of 1 Gb (32 Mb x 32) and a rated frequency of 1250 (5000) MHz, but they are clocked at 1002 (4008) MHz by the card, in full compliance with Nvidia’s official specs. The overclocking potential of the chips is limited by the 384-bit memory bus, so we do not expect to get to their rated frequency in our overclockability tests.
There is nothing extraordinary about the GPU. It is an ordinary GF110 revision A1 chip manufactured on the 46th week of 2010. It is a little bit pre-overclocked, from 772/1544 to 782/1564 MHz. ASUS suggests that further overclocking is up to the user. The GPU works in its full configuration with 512 ALUs, 64 texture-mapping units, and 48 raster back-ends. Despite its nonstandard PCB design, this card proved to be perfectly compatible with a reference GeForce GTX 580. Connected with the flexible bridge included with the ASUS card, they form the SLI tandem we are going to benchmark.
Our sample of ENGTX580 DCII turned out to have high overclocking potential. Its GPU would work at 824/1648 MHz without our resorting to extreme overclocking methods. The memory chips could not make it to their rated frequency and we had to stop at a memory clock rate of 1213 (4852) MHz. Overall, this is a good but not record-breaking result because some samples of GeForce GTX 570 can get as fast as 900 (1800) MHz in terms of their GPU frequency.
You can see the triple-tiered structure the ASUS card in the snapshot. As opposed to an ordinary GeForce GTX 580, the ENGTX580 DCII is additionally equipped with a DisplayPort which is becoming more and more popular. The card can be easily connected to any display device but does not support more than two displays simultaneously (you can make it three displays by enabling SLI mode).