Single page Print

The competition gets a boost
We've been comparing the new GeForce against its siblings in Nvidia's lineup, but of course its natural competition is in the Radeon camp. Apparently the prospect of the Radeon HD 7950 competing against all of these hot-clocked GTX 660 Ti cards was making AMD at little bit uneasy.


Last week, AMD sent us a new BIOS to flash to our Radeon HD 7950 reference cards. This BIOS introduces a new feature, first seen in the Radeon HD 7970 GHz Edition, known simply as "boost." Boost is a fairly straightforward modification to AMD's PowerTune dynamic voltage and frequency scaling algorithm. Before, PowerTune could only reduce clock speeds in response to cases of unusually high GPU demand and power use. With boost, PowerTune can now raise clock speeds (in 4MHz increments) when the thermal headroom allows. Boost also promises more accurate power estimates that enable higher clock frequencies and fuller residency at those speeds.

The flash process was quick and painless. With the boost BIOS, our original Radeon HD 7950 review cards gained a chunk of new performance. The base clock is now 850MHz, up from 800MHz before, and the new boost peak clock is 925MHz. (Memory frequencies are unchanged.)

AMD tells us these clock speeds with boost constitute a new baseline specification for the Radeon HD 7950. The card's list price will remain steady at $349, and board makers should start offering boost-enabled cards at online retailers starting today. Sapphire, HIS, and PowerColor are expected to be first to market.

Current owners of Radeon HD 7950 cards will want to pay attention to this next bit. AMD says all of the Radeon HD 7950 chips shipped to date should be able to run at the clock speeds enabled by the new BIOS. That means a simple BIOS flash offers the prospect of a nice little bump in performance for free. In fact, AMD told us it doesn't mind folks distributing the new, boost-enhanced 7950 BIOS, although we understand this BIOS may not work on cards that vary from the reference design. Eventually, the firm expects boards makers to offer their own custom BIOSes, and those may find their way online, as well.

This fact is more notable because the 7950 reference card includes dual BIOSes, with a second, write-protected copy accessible via a switch just behind the CrossFire connectors. In other words, 7950 owners are pretty much free to attempt an upgrade to the boost BIOS without fear of bricking their cards. If the flash fails, just flip to the backup BIOS and recover.

Even more Radeons
We shouldn't let this focus on the 7950's enhancements distract from the GTX 660 Ti's closest competitor, the Radeon HD 7870 GHz Edition.


No, this isn't the same card pictured on the prior page. This is MSI's Radeon HD 7870 Hawk, with a very similar custom cooler (though with five heatpipes.) The 7870 Hawk is clocked at 1100MHz, 100MHz above the 7870's stock frequency. MSI asks $319.99 for this card.


Before AMD threw us the boost curve ball, we'd already selected a hot-clocked Radeon HD 7950 to use in this review, MSI's R7950 OC Edition. This card lacks a boost BIOS but ratchets up the base clock to 880MHz. The upshot, as you'll see, is performance very similar to the 7950 reference card with the boost BIOS. The R7950 OC Edition has been selling online for a while now at $349.99.

Base
clock
(MHz)
Boost
clock
(MHz)
Peak
ROP rate 
(Gpix/s)
Texture
filtering
int8/fp16
(Gtex/s)
Peak
shader
tflops
Memory
transfer
rate
Memory
bandwidth
(GB/s)
Price
Radeon HD 7870 GHz 1000 - 32 80/40 2.6 4.8 GT/s 154 $299
MSI R7870 Hawk 1100 - 35 88/44 2.8 4.8 GT/s 154 $319
Radeon HD 7950 800 - 26 90/45 2.9 5.0 GT/s 240 $349
MSI R7950 OC 880 - 28 99/49 3.2 5.0 GT/s 240 $349
Radeon HD 7950 w/Boost 850 925 30 104/52 3.3 5.0 GT/s 240 $349

Both the GeForce and Radeon camps now have the space between $300 and $350 firmly covered with options. Fortunately, so do we. We've tested a range of current and older graphics cards in this class. Let's have a look at how they all compare.