PCB Design and Cooling System

Just like it had been the case with Radeon X1800 GTO, ATI Technologies didn’t develop a special PCB for its new card, but took the existing design employed in Radeon X1900 XT/XTX. All samples of Radeon X1900 GT are manufactured at the facilities of Sapphire Technology, the main partner of ATI’s. It means that everything in the subsequent description applies not only to PowerColor’s but also to other companies’ versions of Radeon X1900 GT. The cooling system may differ, however. Radeon X1900 GT cards can be equipped with one of two standard coolers from ATI or, in some cases, with a third-party cooler (e.g. from Arctic Cooling).

The PowerColor X1900 GT’s having fewer pixel processors, TMUs and ROPs active, its power circuitry has been greatly simplified. You can spot this in the right part of the PCB. The power circuit of Radeon X1900 XT/XTX cards includes seven Pulse PA0511.101 inductance coils, but there are only 6 such coils here. The bottommost coil and its accompanying elements are not installed. We didn’t remove the heatsink on the MOSFETs, but we suspect there are fewer of them there, too, due to the low power consumption of the Radeon X1900 GT (you’ll see how the new card compares with the Radeon X1900 XT in terms of power consumption in the next section of the review).

An ordinary R580 graphics processor is installed here and is clocked at 575MHz. Some of its functional subunits are disabled by melting the fuses inside the die package, which makes it impossible to transform the PowerColor X1900 GT into a Radeon X1900 XT. This would be a very appealing option since the R580 chip yield is high and they must mostly be using fully operable chips to make the Radeon X1900 GT. Alas, this overclocking dream won’t come true unless an exclusive batch of cards is released in which the “redundant” subunits are disabled on the BIOS level.

The memory frequency is greatly reduced in ATI’s new solution in comparison with the Radeon X1900 XT and its total amount is cut down from 512MB to 256MB, so the PowerColor X1900 GT carries 8 chips of Samsung K4J55323QG-BC14 GDDR3 memory in 136-pin FBGA packaging. The chips have 256Mbit capacity and work at 1.8V voltage. The memory is rated to work at 700 (1400) MHz frequency, but it is clocked at 600 (1200) MHz here in strict compliance with the Radeon X1900 GT specification. Since the card’s PCB was originally designed for much higher frequencies, we can expect the PowerColor X1900 GT’s memory to reach at least its nominal 700 (1400) MHz clock rate at overclocking.

Like almost all cards on ATI’s GPUs, the PowerColor X1900 GT features a Rage Theater chip for capturing analog video signal. This feature isn’t in high demand nowadays, though. We think they might have not installed this chip at all to reduce the manufacturing cost of the Radeon X1900 GT even further.

We were a little surprised to find on the PowerColor X1900 GT a sample of the old cooler which traces its origin back to the Radeon X1800 XL (we described this cooler in detail in our All-in-Wonder X1800 XL review). This cooler has a lower-performance, but noisier fan in comparison with the new cooler we talked about in our PowerColor X1800 GTO Review. Incorporating heat pipes and a well-ribbed heatsink, this cooler can even cope with junior R520-based graphics card models, but it may find it difficult to handle an R580, even with some of the chip’s subunits disabled. We know that there are versions of Radeon X1900 GT, e.g. the Connect3D Radeon X1900 GT, which feature coolers with an updated design. The older design is probably used because the manufacturer’s got a large amount of such coolers in stock.