PCB Design

Being a large manufacturer, Gigabyte has enough of resources and experience to develop printed circuit boards of any level of sophistication. We can recall this brand to have issued a single-PCB dual-processor graphics card back in 2005, long before the Radeon HD 3870 X2 or GeForce 7950 GX2. It is no wonder then that the GV-R485MC-1GI has a nonstandard PCB, too.

It is the unusual layout of the power circuit that is the most interesting thing here. A GPU voltage regulator is usually located at the back of the PCB, next to a power connector. Here, it is just the opposite: the two-phase regulator is in the front of the PCB, near the CrossFire ports and VGA D-Sub connector. This unusual solution may be questionable, yet we did not observe any stability issues with the GV-R485MC-1GI. The regulator is based on an NCP5392 controller from ON Semiconductor that was originally developed for VRMs of modern Intel and AMD processors.

There are three more power transistors at the back of the PCB. They must be part of the memory voltage regulator. In the same area but on the reverse side of the PCB there is a curious chip marked as Gamer HUD 28280360-ZY.

This chip is responsible for the handy software-based control over the GPU and memory voltage. It is this chip that makes the GV-R485MC-1GI a truly unique product. The GV-N250OC-1GI we have described earlier lacks a Gamer HUD chip, and the related software tool works in Lite mode with it, without giving you the option of flexible control over the graphics card’s power supply. The GV-R485MC-1GI has one power connector, a 6-pin PCIe 1.0 plug with a peak load capacity of 75W, which is more than enough for powering any version of Radeon HD 4850.

There are 8 GDDR3 memory chips on the card. These are Samsung K4J10324QD-HJ1A chips with a capacity of 1Gb (32Mb x 32), a voltage of 1.85V, and a rated frequency of 1000 (2000) MHz. The card’s memory frequency is a standard 993 (1986) MHz. With a 256-bit memory bus, this means a peak memory bandwidth of about 64GBps. The total amount of local memory is 1024MB as has already become standard even for rather inexpensive products such as Radeon HD 4850 or GeForce GTS 250. So much memory is not a crucial advantage because a graphics card can only profit from it at high resolutions where mainstream products are anyway too slow for practical play, yet there is nothing bad in having 1 gigabyte of memory on board. Moreover, 1GB of local graphics memory may come in handy if you are going to build a multi-GPU tandem out of two such cards that would allow playing at 1920x1200 and even at 2560x1600.

The RV770 chip installed on the GV-R485MC-1GI was manufactured in late July of the last year. Its frequency of 640MHz is somewhat higher than the official specs (625MHz) but the difference is not big enough for considerable performance benefits.

The graphics core has the maximum configuration possible with 800 ALUs, 40 TMUs, and 16 RBEs. There are no disabled subunits in it.

The card’s connectors are what you can often see on today’s HTPC-oriented products including a physical HDMI port to connect to LCD panels without adapters. There are slits in the top part of the card’s mounting bracket the cooler’s heatsink ribs poke through (we will discuss it below). Like every other Radeon HD 4850, the GV-R485MC-1GI can work in a CrossFireX subsystem, offering two standard connectors for that.