Clock Rates And Lethal Boost Mode
Overclocking with the Push of a Button
Engaging Lethal Boost mode is pretty simple: push the Lethal Boost button while the computer is running and then re-boot. The Toxic HD 7970 GHz Edition loads its settings from a second firmware containing higher clock frequencies and a more aggressive fan profile.
First, we have the original factory settings:
Then we push the Lethal Boost button. In the picture below, the button is to the left of the CrossFire connectors.
Lethal Boost Mode now gives us higher clock rates and a new PowerTune limit that extends to 50 percent (from 20).
When the Radeon HD 7970 GHz Edition launched, we discovered that if the card gets overclocked (or underclocked) by only 1 MHz, it holds that frequency, behaving like an ordinary Radeon HD 7970. It doesn’t throttle down, though, even when it's idle. The card sucks down 50 W or so, and ZeroCore Power stops working. We use the fixed clock rate to compare Sapphire's Toxic HD 7970 GHz Edition 6 GB to older cards.
Our Benchmark System
|Header Cell - Column 0||Benchmark System (Open Case)|
|CPU||Core i5-2500K (Sandy Bridge), Overclocked to 4.5 GHz|
|Cooler||Prolimetech Super Mega + Noiseblocker Multiframe|
|Memory||4 x 4 GB Kingston HyperX DDR3-1600|
|Motherboard||Gigabyte Z68X UD7-B3, Z68 Express|
|Operating System and Driver||Windows 7 Ultimate x64 Catalyst 12.6 WHQL|
|Case||Lian Li PC-T60A ATX Test Bench|
First Benchmarks At Stock Settings
We started by taking a quick look at how the Sapphire Toxic HD 7970 GHz Edition 6 GB fares at its stock settings. This gives us a reference point for our more in-depth benchmarks.
Our second test, Metro 2033, was also run at 1201 MHz, fixing its clock rate in place.
At a resolution of 2560x1440 pixels, Sapphire's Toxic HD 7970 GHz Edition 6 GB and Gigabyte's Radeon HD 7970 Super Overclock with 3 GB perform about the same. The Gigabyte card does manage to deliver better power consumption results compared to Sapphire's board at this fixed clock rate, interestingly enough.
Seeing as in both SLI and CFX memory contents are copied to each card, you would practically need that much for ridiculously large screen playing. One card can not handle multiple screens as this was designed for, you need at least two for a x4 screen and three for a x6 screen. The golden rule seems to be two screens per high end card.
BigMack70Would be very interested in seeing this in crossfire at crazy resolutions compared to a pair of 3GB cards in crossfire to see if the vram helps in that case
Tom's Hardware, if you are going to be reviewing a graphics card with 6 GB of VRAM you have to review at least two of them in Crossfire. VRAM is not cumulative, so using two regular HD 7970 3 GB in Crossfire still means that you only have a 3 GB framebuffer, so for high resolutions with multiple monitors, 6 GB might make the difference.
So, are we going to get an update to this review ? As it is it is useless. Make a review with at least two of those cards with three 30" 1600p monitors. That is the kind of setup someone considering buying one of those cards will have. And that person won't buy just one card. Those cards with 6 GB of VRAM were made to be used at least in pairs. I'm surprised Sapphire didn't tell you guys that in the first place. In any case, you should have figured it out.
Thanks for the review. The noise demo alone helps in making a purchase decission.
No sale !
Anyone know why no card has been designed to be turned OFF ( 0 Watts !) when idle, and the system switching to internal graphics for just desktop stuff or simple tasks?
Then applications like Photoshop, Premiere or the ever popular Crisis could 'wake up' the card and have the system switch over.
Or are there cards like that ?
I think that has been applied to laptops, but not on the desktop scene. One of the reasons why I would think its not as useful on a desktop scene is even if your build has stuff off, the PSU is the least efficient when on near 0% load, so no matter what, your still going to burn electricity just by having the computer on. All gpus nowandays have downclocking features when its not being on load(my 7850 downclocks to 300mhz on idle) but I wouldnt think cards will go full out 0.