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PCB Design and Specifications

The Zotac is very compact and much shorter than the reference sample from Nvidia. That’s good. Of course, it is also smaller than the GeForce GTS 250 but the latter is too old to be compared with a newly released product.

The new card can easily fit into most system cases, except for the smallest ones which are designed for single-slot graphics cards. Yes, even this affordable Fermi-based solution needs a dual-slot cooler for its 1.17 billion transistors with a TDP of 100 watts. On the other hand, the Radeon HD 5750 has similar dimensions. We removed the cooling system to have a better view of the hardware components:

The card is much simpler than its Fermi-based cousins, especially the GF100-based ones. Its power circuit represents a 3+1 design with a 3-phase GPU voltage regulator and a single-phase regulator of GDDR5 memory voltage.

The GPU voltage regulator is managed by a NCP5395 controller from ON Semiconductor. This chip is also used on the GeForce GTX 460 cards from Palit/Gainward. An APW7165 controller from Anpec Electronics is responsible for the memory chips. It is a rather popular controller, being present in the reference designs of GeForce GTX 460, 465 and 470 as well as in some other graphics card models (we have seen it in an XFX Radeon HD 5830, for example). There is only one power connector, so there should be no problems connecting the GeForce GTS 450 to a power supply. Even cheap PSUs offer at least one 6-pin PCIe 1.0 connector nowadays. But if your PSU doesn’t have one, the Zotac GeForce GTS 450 AMP! comes with an appropriate adapter.

The two empty seats for GDDR memory chips on each side of the PCB indicate that the GF106 processor indeed supports a 192-bit memory bus, but the current version of the GF106-based card has a 128-bit bus only.

There are eight 1Gb GDDR5 chips from Samsung Semiconductor on this card. Zotac uses fast K4G10325FE-HC04 chips capable of working at a frequency of 1250 (5000) MHz. Such fast memory is only used on the GeForce GTX 480 and some models of the Radeon HD 5800 series. Coupled with the 128-bit bus, this should yield 80 GBps, but Zotac set the memory frequency at 1000 (4000) MHz for a peak bandwidth of 64 GBps. This is still faster than the reference card’s 902 (3608) MHz and 57.7 GBps. The Zotac supports two power-saving modes in which the memory frequency is lowered to 324 (1296) MHz or to 135 (540) MHz, depending on graphics load.

The GF106 processor looks quite extraordinary, lacking the heat-spreading cap typical of the more advanced Fermi series solutions as well as of the top-performance GPUs of the previous generation. The die is rather large for an affordable GPU, measuring about 240 square millimeters, which is but slightly smaller than the 55nm G92’s size of 270 square millimeters. The GF106 looks quite impressive compared with the modest 170 square millimeters of the ATI Juniper chip. For a die that large, the protective frame is a must. The GPU marking indicates a second revision of the graphics core and shows the manufacturing date of the sample installed on the Zotac card. It is the 30th week of 2010, so the GF106 was being mass-produced in July, long before the official announcement.

The graphics core has the maximum GeForce GTS 450 configuration with 192 ALUs, 32 TMUs and 16 RBEs. One of the physically available 64-bit memory controllers is turned off together with its eight RBEs. We’ve said above that Nvidia chose rather odd reference frequencies for the new card, but Zotac’s version of the GeForce GTS 450 is pre-overclocked from 783/1566 MHz to 875/1750 MHz, which is a promise of a rather high performance growth. The GPU voltage is 0.962 volts in the 3D mode. Like the rest of Nvidia’s Fermi solutions, the power-saving modes reduce the GPU frequencies to 405/810 MHz and to 51/101 MHz in applications with low graphics load, e.g. during HD video playback.

The Zotac GeForce GTS 450 AMP! is equipped with all modern interfaces for connecting to display devices: DVI, HDMI and DisplayPort. Analog connection is supported by means of a D-Sub adapter. The card also supports Nvidia SLI and Surround Gaming technologies but the latter in 2D mode only: even a pair of GeForce GTS 450 is going to be not strong enough to maintain a playable frame rate in 3D Vision mode. As for audio, the card can transmit not only ordinary audio streams but also multichannel streams in Dolby TrueHD and DTS-HD Master Audio formats over HDMI. This functionality used to be only available on the Radeon HD 5000 series until recently.

The Zotac GeForce GTS 450 AMP! comes with an extremely simple cooler: an ordinary 80mm fan is blowing at a one-piece aluminum heatsink fastened to the PCB with four spring-loaded screws.

The heatsink’s sole is not finished perfectly and is not absolutely smooth. A lozenge of dark-gray thermal grease serves as a thermal interface here. The memory chips and power system components do not have any special cooling. The chips on the face side of the PCB get some airflow from the fan while the chips on the reverse side do not have even that. Well, they do not heat up much and can hardly overheat. Considering the less advanced specifications in comparison with the GF104, the GF106 is going to consume less power, so the above-described cooler should be able to cope with the GeForce GTS 450 even at pre-overclocked frequencies like those of the Zotac version.

 
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