PCB Design and Specifications
PowerColor ships its HD6950 1GB in an upright box like the one with the HD6870 PCS+ card that we tested earlier. The only difference is the picture on the face side which is reminiscent of the Warhammer 40K universe.
That’s not the most popular of game settings, but it’s a matter of taste. The box design is neither original nor informative. You can only see the card’s model name as well as the type and amount of its graphics memory.
There is a simple cardboard tray inside the box, which is not much in terms of protection. Besides the graphics card in an antistatic pack, we found the following in there:
- DVI-I → D-Sub adapter;
- Mini DisplayPort → DisplayPort adapter;
- Installation guide;
- CD disk with drivers and utilities.
The accessories are even scantier than those of the HD6870 PCS+. There is even no CrossFire bridge here. On the other hand, the lack of accessories helps lower the price of the product which, along with performance, is the crucial factor for the majority of users.
Oddly enough, the PowerColor HD6950 1GB uses a slightly revised Radeon HD 6870 design rather than the reference Radeon HD 6950 PCB developed by AMD. We saw this very PCB in our review of the HD6870 PCS+:
There are some discrepancies, of course, but we can’t see them until we take off the cooler by unfastening the four spring-loaded screws:
There are actually but a few differences from the HD6870 PCS+. We can see a slightly different wiring of the ground in the back part of the PCB and some changes in the top left corner due to the second CrossFire connector and BIOS switch. PowerColor engineers seem to have made the most of the resources they already had at hand.
The 4-phase GPU voltage regulator is based on a CHiL Semiconductor CHL8214 controller whereas the memory subsystem is based on a controller from uPI Semiconductor marked as uP1509P. The overall design of the power circuit hasn’t changed. It still represents the 4+2 formula and receives external power via two 6-pin PCIe 1.0 connectors.
Hynix’s 1Gb H5GQ1H24AFR memory chips (32 Mb x 32) are installed on the PowerColor card. Their T2C suffix denotes a rated frequency of 1250 (5000) MHz which is indeed the frequency the card clocks its memory at, delivering a peak bandwidth of 160 GBps. We don’t expect these chips to be good at overclocking but the PowerColor HD6950 1GB already seems to have enough of memory bandwidth to begin with.
The card’s GPU was manufactured on the 49th week of 2010. Of course, it is a cut-down version of the Cayman processor with only 1408 ALUs active out of the total 1536 available in the GPU die. Thus, there are only active 352 VLIW4 processors out of the total 384. The texture-mapping subsystem is reduced from 96 to 88 TMUs whereas the rasterization subsystem has remained intact because the memory controller configuration depends on it. So, the 32 raster back-ends available in the GPU die are all active here.
The GPU clock rate is 250 MHz in power-saving mode and 800 MHz at full load, which complies with AMD’s official Radeon HD 6950 specs. The GPU voltage can be set at one of three values: 0.898, 1.0 or 1.063 volts, depending on the operation mode. There is a BIOS switch in the top left of the PCB which allows switching between the read-only factory BIOS and the rewritable version that can be modified by the user.
You can see a standard configuration of interfaces on the mounting bracket of the PowerColor HD6950 1GB: two DVI-I ports, one HDMI and two mini-DisplayPorts. You can use all five simultaneously. And if you employ a DP 1.2 switch, you can even make the card output visual content to as many as six monitors. The two CrossFire connectors allow building a top-performance multi-GPU subsystem consisting of up to four such cards. Perhaps the recently released Radeon HD 6990 doesn’t make such a quad-GPU configuration very appealing, yet some users might want to use this opportunity.
As we noted in our PowerColor HD6870 PCS+ review, that card’s cooling system was very poor or downright defective. The HD6950 1GB comes with a similar cooling solution:
The heatsink is larger but there are still only two heat pipes. There are two 92mm fans to blow at the heatsink. We’d call this cooler promising if we hadn’t had a disappointing experience with the PowerColor HD6870 PCS+. Let’s check it out anyway.