PCB Design, Specifications, Cooling System

As opposed to the EVGA GeForce GTS 250 Superclocked, Gigabyte’s card uses a unique PCB developed especially for the Ultra Durable series. The PCB is 2 centimeters shorter than the reference card. It is only 21 centimeter long.

This compactness is mainly achieved by compacting the GPU voltage regulator using small low RDS(on) MOSFETs. But like on the reference PCB, the regulator has four phases and is based on an ON Semiconductor NCP5388.

The memory voltage regulator is based on two STMicroelectronics D1703L MOSFETs and seems to be controlled by the miniature chip marked as CD-N2B and designated as U1 on the PCB. The card has only one power connector but it is placed at the shorter edge of the card. This should not be a problem even for compact system cases considering the shorter length of the PCB. The stricken-out letters Pb indicate that lead and its compounds are not used in the manufacturing process.

As we’ve promised above, we will know tell you about the unique technology of some Gigabyte products including the GV-N250OC-1GI. It is called 2oz Copper PCB. What do those ounces stand for? Well, the marketing folks bring confusion into descriptions of even simple things and technologies. Here, the point is that the PCB’s metallization layers are double the usual thickness – 70 rather than 35 micrometers. If calculated for a square foot of PCB, this results in a 2oz increase in the mass of employed copper. That’s why the name is 2oz Copper PCB. This technology is not just pure marketing, though. Hot components like the GPU or power transistors of the voltage regulator heat up the PCB underneath them. And as copper has excellent thermal conductivity, the thicker metallization layers should improve the PCB’s ability to dissipate heat and thus help in cooling those components. Gigabyte claims that the GPU temperature of Ultra Durable VGA series with 70-micrometer copper interconnects is 5 to 10% lower than that of cards with ordinary 35-micrometer metallization. Gigabyte’s thermographic pictures look convincing enough. We cannot check this out by ourselves, yet the improvement in cooling does agree with theory.

Like the above-described EVGA GeForce GTS 250 Superclocked, the Gigabyte GV-N250OC-1GI is equipped with Hynix H5RS1H23MFR-N2C chips that have a capacity of 1 gigabit and a rated frequency of 1200 (2400) MHz. The card’s memory frequency agrees with Nvidia’s official specs and is 1100 (2200) MHz. With a 256-bit bus this ensures a peak memory bandwidth of 70.4GBps.

The graphics core is marked as G92-421-B1. It was manufactured on the 42nd week of 2008, i.e. in the middle of October. In full accordance with Nvidia’s official GeForce GTS 250 specs, the GPU has a frequency of 738MHz and 1836MHz for the main and shader domain, respectively. The GPU has the maximum configuration possible for the G92/G92b processor: 128 ALUs, 64 texture-mapping units, and 16 raster back-ends.

Gigabyte has tried to make its product modern and universal. Therefore the GV-N250OC-1GI does not support the obsolete analog video formats like S-Video and others. Instead, it offers a dedicated HDMI port with protective cap. Besides, the mounting bracket accommodates D-Sub VGA and DVI-I ports. This makes the card suitable for both gaming systems and HTPCs, especially as a cable for translating S/PDIF audio into HDMI is included into the box. Gigabyte does not think that anyone will build Triple-SLI configurations out of GeForce GTS 250 and offers only one MIO connector on the card. It has a protective cap, too.

The GV-N250OC-1GI is equipped with a somewhat simplified version of the Zalman VF1000 cooler. It is called Zalman VF1050. It is simplified because it lacks a universal fastening mechanism and uses a fan with 2-pin connection. Otherwise, this is a full-featured cooler following the best design tradition of Zalman. The cooler’s nickel-plated heatsink look very beautiful in combination with the blue color of the PCB.

In fact, the heat-exchanger and the heat pipes are made from copper but the heatsink’s plates are from aluminum. We did not see the characteristic red color of copper when we tried to scratch them. And moreover, the assembled cooler weighs only 225 grams. It would be much heavier if the heatsink were made from copper. This should not be a problem, however. The Zalman VF1050 should be quite able to cope with the G92b chip easily and noiselessly even without a copper heatsink. The fan is blowing sideways as well as downward, thus lowering the temperature of the PCB with its components. Coupled with the thicker metallization layers, this should make the cooling of the GV-N250OC-1GI even more effective.

A layer of dry dark-gray material is used as a thermal interface between the heat-exchanger’s sole and the GPU die. We can’t even call it thermal grease because the stuff is like regular glue, fastening them both into a single whole. The cooler is fastened to the PCB with four threaded poles and spring-loaded nuts. There is no misalignment, so the single drawback of this cooling system is that the hot air is not exhausted out of the system case. The cooler looks highly promising overall.