In Buildzoid’s latest PCB breakdown video he veers away from examining one of today’s modern VGA card offerings, preferring instead to revisit what he regards as a real classic design from the not too distant past. The card in question is a GIGABYTE HD 7970 SOC card, a card that Buildzoid describes as ‘one of the most complicated and awesome PCBs ever made’.
The Super Overclock range of VGA cards from GIGABYTE are indeed cards that are designed to stand up the rigors of overclocking, indeed they arrive with a tasty factory-defined overclock out of the box. The PCB features a VRM design that in many ways is actually perfect for any kind of overclocking, Extreme or otherwise. The design is, in Builzoid’s own words, ‘pretty freaking awesome’ with GIGABYTE going ‘a little insane’.
Examining the PCB in typical detail we find that the GPU itself is blessed with an eight-phase VRM that stretches the full height of the card (i.e. it is as substantial as it is physically possible to be without using a taller PCB), plus two additional phases for the memory and two more phases (quite uniquely) for the auxiliary power delivery. This is already shaping up to be a very strong power delivery design, bordering on overkill. But it doesn’t stop there.
The GPU’s core voltage delivery features eight phases, uses eight conductors (or chokes), plus eight power stages, controlled by a CHL 8228 digital muliti-phase buck controller from CHiL (a subgroup of International Rectifier now owned by Infineon). The presence of the CHL chip means you’re getting a true eight-phase VRM. This is in contrast to most of today’s AMD cards which tend to use IR controller chips that are limited to six phases. A CHil 8225 controller chip is used to form a true two-phase design for the memory alone. Again, pretty much overkill compared to today’s designs.
As you would expect from Buildzoid, there is a great deal of detail to be absorbed in this video as he explains the component choices on the PCB and the design decisions that possibly led up to them. It’s a great watch for any hardcore Overclocker interested in exploring a classic VRM design. Catch the video here on the Actually Hardcore Overclocking YouTube channel.