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PCB Design

As opposed to the PowerColor X1950 Pro Extreme, the X1950 Pro SCS3 uses a different PCB design that was developed by ATI/AMD’s main production partner Sapphire Technology:

The new and presumably less expensive PCB resembles the original reference Radeon X1950 Pro design with its unique high-frequency power circuit with few electrolytic capacitors and a peculiar position of the power connector. There are considerable differences, however, concerning the power circuit mostly.

The new power circuit has a more conventional design with traditional capacitors and power MOS transistors. The GPU power regulator is based on a two-phase PWM controller Nexsem NX2415. A chip marked as “P2322WF A1” seems to be responsible for controlling memory power supply. Among six transistors on the face side of the PCB in the power circuit area, four are cooled with small aluminum heatsinks fastened with thermal glue. The PCB design didn’t originally intend any special cooling for the power elements, but it is needed here due to the use of a fully passive cooling system and thus the lack of any airflow. The power connector has returned to its customary place in the top right corner of the PCB.

The modular approach applied in the design of ATI/AMD’s PCBs has helped avoid spending much effort to develop the new PCB. Apart from the new power circuit, the PCB is identical to the one we described in our review of the Radeon X1950 Pro called ATI Radeon X1950 Pro against Nvidia GeForce 7900 GS, except for the slightly different configuration of the screen. The Rage Theater chip, endowing the card with VIVO functionality, is in its place, too. There’s little use from it in the year 2007, but some people may find it helpful, especially if the PowerColor X1950 Pro SCS3 is going to be utilized in a home multimedia center.

The two connectors in the top left corner of the PCB are needed for building a CrossFire subsystem in which two PowerColor X1950 Pro are connected to each other with special flexible cables.

The card carries eight GDDR3 chips (256Mb, 8Mx32) providing a total of 256 megabytes of graphics memory with a 256-bit bus. Small heatsinks are glued to the chips. The glue proved to be very strong and we couldn’t remove a heatsink for fear of damaging the card. We suppose the chips are Samsung K4J55323QG-BC14. The memory frequency is 690 (1380) MHz which exactly complies with AMD's official specification.

We know that the Radeon X1650 XT and Radeon X1950 Pro GPUs are in fact one and the same die that is installed, depending on the version of the GPU, into a package with a 128-bit or 256-bit memory bus. This is probably why they are not marked as RV560 and RV570, respectively. The version with a wider bus is always marked as “215PADAKA12FG”. Our sample was manufactured the third week of the current year, i.e. in late January. It is clocked at 575MHz, just as described in the official Radeon X1950 Pro specification. The GPU package is equipped with a metallic frame to prevent the cooler from misaligning and damaging the die. This frame is virtually useless here, however, as we’ll explain shortly.

 
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