Sapphire Toxic HD 7970 GHz Edition Review: Gaming On 6 GB Of GDDR5

Sapphire gives its new flagship graphics card 6 GB of very fast memory, compared to the mere 3 GB on AMD's reference card. Does this give Sapphire's Toxic HD 7970 GHz Edition a real-world speed boost? We connect it to an epic six-screen array to find out.
Sapphire’s new flagship graphics card, the Toxic HD 7970 GHz Edition 6 GB, has two times as much GDDR5 memory as AMD's reference Radeon HD 7970 GHz Edition board. The company employs the same GPU discussed in AMD Radeon HD 7970 GHz Edition Review: Give Me Back That Crown!, allowing its own Lethal Boost technology (essentially automatic overclocking) to take the chip up to 1200 MHz and the memory to 1600 MHz when thermal headroom allows. The combination of a faster clock rates and extra memory should yield a nice performance boost for the folks who know how to capitalize.
Wait. There are ways to take advantage of all of that memory, aren't there?
Lots of extra RAM is most effective at high resolutions and with lots of anti-aliasing applied. So, that's what we'll be looking most closely at today.

Nothing says big resolutions like an Eyefinity setup composed of six monitors. You might think that we'd need a special Eyefinity Edition of the Radeon HD 7970 to achieve such a thing, but it's indeed possible using a trio of splitters. The only question to answer is whether the card's single Tahiti GPU is fast enough to drive such a massive setup.
Speaking of massive, we decided to go all-out for this little experiment, making it a public event. Our point of comparison was the Radeon HD 7970 from Gigabyte, which we recently reviewed in Gigabyte Radeon HD 7970 Super Overclock: Now With Windforce 5X. For the sake of our head-to-head, we overclocked the Gigabyte board to 1200 MHz, giving us a good baseline for 3 GB versus 6 GB of memory.

Technical Specifications and Features

Sapphire naturally went with AMD's Tahiti GPU for its top-end board, including the built-in TDP limiter that throttles clock rate beyond a set thermal ceiling. We'll be testing to see if that turns out to be a good move. The card's 6 GB of memory running at 1600 MHz represents the most you'll probably ever see from this platform.

Here's how the card's technical specifications size up to AMD's original Radeon HD 7970, the GHz Edition card, and Gigabyte's take on the board:

	Sapphire Toxic HD 7970 GHz Edition	Gigabyte Radeon HD 7970 Super Overclock	Radeon HD 7970 GHz Edition	Radeon HD 7970
Stream Processors	2048	2048	2048	2048
Texture Units	128	128	128	128
Full Color ROPs	32	32	32	32
GPU Clock	Standard: 1050 MHz Base 1100 MHz Boost Lethal Boost: 1100 MHz Base 1200 MHz Boost	1080 MHz	1000 MHz Base 1050 MHz Boost	925 MHz
Texture Fill Rate	140.8 MHz Gtex/s 153.6 Gtex/s	138.2 Gtex/s	134.4 Gtex/s	118.4 Gtex/s
Memory Clock	1500 MHz 1600 MHz	1375 MHz	1500 MHz	1375 MHz
Memory Bus	384-Bit	384-Bit	384-Bit	384-Bit
Memory Bandwidth	288 GB/s 307.2 GB/s	264 GB/s	288 GB/s	264 GB/s
Graphics Memory	6 GB GDDR5	3 GB GDDR5	3 GB GDDR5	3 GB GDDR5
Die Size	365 mm²
Transistors	4.31 Billion
Process Technology	28 nm
Power Connectors	2 x 8-pin	2 x 8-pin	1 x 8-pin, 1 x 6-pin	1 x 8-pin, 1 x 6-pin
Maximum Power Consumption (TDP)	320 W	300 W	275 W	250 W

Sapphire's card features one dual-link DVI, one single-link DVI, one HDMI, and two Mini DisplayPort connectors. This makes the Toxic HD 7970 GHz Edition 6 GB more flexible than even AMD's reference design. The card's bracket employs openings for better ventilation, though its axial fans don't necessarily promote effective exhaust.

	Description
Dimensions	275 (L) x 115 (H) x 42 (D) mm
Included Software	Driver CD Sapphire TriXX
In the Box	CrossFire Bridge, DVI-to-VGA Adapter, Mini DP-to-DP Adapter, Active Mini DP-to-DVI Adapter, 6-pin to 2 x 4-pin Power Cable, 1.8 m HDMI 1.4a Cable

Sapphire's Toxic HD 7970 GHz Edition 6 GB in Pictures

Sapphire’s Vapor-X cooler was developed specifically for this card. Visually, it looks similar to Sapphire's other cards. However, you can see the special vapor chamber under the plastic shroud and two 90 mm fans.

Sapphire deviates from AMD’s reference design with a 12-layer PCB populated with what the company calls its Black Diamond chokes and MOSFETs with DirectFET packaging technology on both sides. The card’s backplate is used to both stabilize and cool the card. We'll go into more depth on this, of course.

The top of Sapphire's Toxic HD 7970 GHz Edition 6 GB has two much-needed eight-pin power connectors.

Sapphire's logo lights up, which looks pretty sharp in the dark.

The cooler employs four heatpipes.

The Sapphire Toxic HD 7970 GHz Edition 6 GB is quite thick, almost making it a three-slot card. You need the right motherboard to run two of these in CrossFire.