PCB Design

Palit’s card obviously differs from the reference Radeon HD 4870 X2. It has a very tall cooling system that has a triple-slot form-factor. It also has a nonstandard selection of I/O ports. You can see two large fans that are meant to cope with a Radeon HD 4870 X2 without making much noise:

Palit Revolution 700 Deluxe

PowerColor HD 4870X2 2GB GDDR5 (reference design)

As usual, the most exciting things are hidden under the cooler’s heatsinks, so we removed them. That was easy enough.

Palit Revolution 700 Deluxe

PowerColor HD 4870X2 2GB GDDR5 (reference design)

The PCB design is largely borrowed from the reference ATI card. That’s wise since developing such a PCB from scratch is a time-consuming and costly affair. On closer inspection you can note a number of small differences, so this design can be considered unique. Most of the differences are in the area of the card’s mounting bracket and power connectors. As opposed to the reference Radeon HD 4870 X2, the latter are placed flat on the PCB, making it easier to plug the connectors in if the card is already installed into the system case. The power subsystem is copied from the Radeon HD 4870 X2 and consists of two independent three-phase GPU voltage regulators, each of which is based on a dedicated Volterra VT1165 controller. And there are also two one-phase memory voltage regulators.

As we found in our earlier reviews, the 8-pin PCIe 2.0 power connector is required for the Radeon HD 4870 X2 because its load exceeds the load capacity of the 6-pin PCIe 1.0 connector (75W).

A PEX8647 switch from PLX Technology is responsible for the communication between the graphics cores and the PCI Express 2.0 interface.

The switch has 48 lanes and supports direct communication mode for the GPUs. An additional communication channel between the GPUs called Sideport is present but is still disabled. It will hardly be turned on in the current generation of dual-processor ATI Radeon HD series products.

There are two sets of GDDR5 memory chips on board: eight chips for each GPU. Half of the chips are installed on the reverse side of the PCB as there is no place for them on the face side. The chips are Qimonda IDGV1G-05A1F1C-40X. They have a capacity of 1Gb (32Mb x 32), a voltage of 1.5V, and a rated frequency of 1000 (4000) MHz. The memory frequency of the reference Radeon HD 4870 X2 is 900 (3600) MHz but the Palit version is slightly pre-overclocked to 950 (3800) MHz. Such a small frequency growth can hardly affect the gaming performance of the Revolution 700 Deluxe much, though.

The PCB is equipped with two RV770 graphics cores clocked at 790MHz, which is also slightly higher than the reference card’s 750MHz. Both GPUs are dated the 40th week the last year and are rather old. As usual, they have the maximum configuration possible for the RV770 chip: 160 superscalar computing modules, 40 texture processors and 16 RBEs per each graphics core. This is an impressive arsenal and our readers already know how brilliantly a Radeon HD 4870 X2 can perform in games with its total of 1600 ALUs, 80 TMUs and 32 RBEs.

As opposed to the ordinary Radeon HD 4870 X2, the Revolution 700 Deluxe offers connectors for every type of a monitor available today: D-Sub VGA, DVI-I, HDMI and DisplayPort. This makes it a truly universal device that only lacks support for analog video outputs, but analog interfaces are hardly required anymore. These I/O connectors have a potential inconvenience, though. If you’ve got two monitors with DVI interface, the connection through the included HDMI→DVI-I interface is less reliable as it has an extra link in the chain. It also does not look tidy. The D-Sub connector is connected to the PCB via a flexible cable which can affect image quality at high resolutions. This may be a problem for obsolete CRT monitors and for early TFT panels with a diagonal of 24 inches that do not have a digital interface. Owners of such monitors can try to use the DVI-I→D-Sub adapter instead.

Besides the I/O ports, there are slits in the card’s mounting bracket that are theoretically meant for the hot air to leave the system case, but these slits perform almost no function as we will explain shortly.

Like the reference card from ATI, the Palit Revolution 700 Deluxe can work in a quad-processor CrossFireX subsystem and offers an appropriate onboard connector for that. It is alone there, meaning that you cannot unite more than two cards together. On the other hand, even this kind of a graphics subsystem will largely be overkill. As opposed to traditional dual-processor multi-GPU solutions, its compatibility with games is worse but it has a terribly high level of power consumption and heat dissipation. Besides, installing two such cards into the same computer does not sound reasonable to us because of the triple-slot cooling system installed on the Revolution 700 Deluxe.