PCB Design and Specifications
The reference GeForce GTX 460 1GB resembles all recent top-class products from Nvidia as it uses a cooling system with blower that exhausts the hot air out of the system case.
The card looks heavier than the Gainward GeForce GTX 460 GS GLH we reviewed earlier and is longer. Not much longer, though, so the Zotac can be installed into most system cases easily. You may only have problems connecting the power cables in a short chassis: as opposed to the Gainward card, the Zotac has its power connectors at the shorter edge of the PCB rather than at the top edge.
The component layout resembles that of the above-mentioned Gainward. One of the memory chips is placed separately from the others, next to the DVI connectors. The power circuit is designed like 3+1, the 3-phase GPU voltage regulator being controlled by an NCP5388 chip from ON Semiconductor. The same controller is used in GeForce GTX 470 and 465 cards.
The MSI Afterburner tool supports this chip but the top limit for the GPU voltage is 1.087 volts. This limitation can only be removed by using a modified BIOS but our attempt to do so failed and we had to restore the original BIOS. An Anpec Electronics APW7165 chip is responsible for powering the graphics card’s memory. We saw it before, for example on the GeForce GTX 465. Like the Palit version, the reference GeForce GTX 460 receives external power via two 6-pin PCIe 1.0 connectors.
The card is equipped with K4G10325FE-HC05 memory chips from Samsung Semiconductor that have a capacity of 1 Gb (32 Mb x 32) and a rated frequency of 1000 (4000) MHz. As opposed to the Gainward GeForce GTX 460 1GB GS GLH, the card has the reference memory frequency of 900 (3600) MHz. This is not high, at least in combination with its 256-bit memory bus, compared to AMD’s solutions. The total amount of onboard memory is 1024 megabytes, which is enough for any modern application or game. The card can lower its memory frequency to 324 (1296) MHz and to 135 (540) MHz depending on the running application: the former mode is for video playback and the latter is for 2D office applications. The Zotac is no different from the Gainward GeForce GTX 460 1GB GS GLH in this respect.
Our Zotac GeForce GTX 460 1GB has an A1 revision GF104 chip manufactured on the 23rd week of 2010. The GPU works in its maximum configuration available today: 336 ALUs, 56 TMUs and 32 RBEs. The card has the reference GPU clock rates: 675 MHz for the main domain and 1350 MHz for the shader domain. The GPU frequencies are lowered to 405/810 MHz and 51/101 MHz in the two power-saving modes. The core voltage in 3D mode is 0.987 volts. It lowers to 0.912 and 0.875 volts in the first and second power-saving mode, respectively. As we wrote above, the highest voltage you can set with software tools is 1.087 volts. You have to modify the card’s BIOS to achieve higher values. The current version of GPU-Z still reports the parameters of GF104-based cards incorrectly, particularly the number of active shader processors. You shouldn’t worry about the number 224 reported by this tool. It doesn’t mean that the graphics card is defective. In fact, the card has 336 active ALUs (out of the total of 384 which are physically present in the GPU).
Nvidia’s reference sample has a more up-to-date set of interfaces than the Gainward card. It has every popular digital interface, including DisplayPort, and supports D-Sub via an adapter. There is one MIO connector for uniting two GeForce GTX 460s into a SLI tandem. The Zotac card worked without any problems in SLI mode during our tests.
The reference cooling system of the GeForce GTX 460 is simple and not new, tracing its origin from the GeForce 8800 GTX’s cooler. However, it uses direct-touch technology, which means that the heat pipes have direct contact with the GPU’s heat-spreading cap. We’ve already seen this technology in the coolers of GeForce GTX 480, 470 and 465 series cards. Oddly enough, there are no thermal pads for the memory chips and power system components.
You can read the fan marking in the photo. The Protechnic MGT8012YB-W20 model is well known to everyone who prefers Nvidia products because this fan is installed into most reference coolers from Nvidia. Depending on its speed, the fan can be anything from very quiet to as loud as a vacuum cleaner.
The heatsink is rather small and its heat dissipation area isn’t large, especially in comparison with the cooler installed on the Gainward card. Yes, it should cope with the GF104 well enough, yet we do not expect a low temperature. We’ll check this out in the next section of this review but we guess the GeForce GTX 460 calls for a more serious heatsink. We are also skeptical about the two-tier placement of the DVI connectors. The result is that there are fewer vent holes in the card’s mounting bracket for the cooling system to exhaust the hot air. You’ll learn how this affects the card’s cooling in the next section of our review.