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AMD Radeon HD 7950 Review: Up Against GeForce GTX 580

AMD Radeon HD 7950 Review: Up Against GeForce GTX 580
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When the Radeon HD 7970 launched at $550, it looked like a reasonable alternative to the GeForce GTX 590 and Radeon HD 6990. Both dual-GPU boards are measurably faster, but they’re also $700+, power-hungry, and in the case of the 6990, embarrassingly loud. Even still, the 7970's asking price is still pretty steep.

And that’s why a card like the Radeon HD 7950 is such a welcome addition to AMD’s portfolio. The company is, as of this writing, unwilling to comment on the 7950’s anticipated price tag. However, we’ve already run the benchmarks. We know how it stacks up to the Radeon HD 7970 and GeForce GTX 580. So, we know what we’d pay for this new board. If our target is close, we’d be looking for something under $500—perhaps $480 or $490.

What makes the Radeon HD 7950 worth a few bucks more than Nvidia's GeForce GTX 580? Well, let’s have a closer look at the card itself…

Update: Before publication, but after our launch coverage was finalized for international translation, AMD let us know that the Radeon HD 7950 should sell for $450. That's well below where I thought the company would target, given its competition. Clearly, AMD is pricing the 7950 to out-value Nvidia's GeForce GTX 580 (or force its competitor to adjust downward) rather than exist in a price structure defined by the company's single-GPU flagship. Advantage: AMD.

That's a Radeon HD 7970 up top and a Radeon HD 7950 down below. In the right light, they'd pass as twins.

Meet AMD’s Radeon HD 7950

Physically, the Radeon HD 7950 is identical to AMD’s already-available Radeon HD 7970—save one distinguishing feature: a second six-pin auxiliary power connector. That’s a telltale indication of a sub-225 W maximum board power (75 W from the slot, plus up to 75 W from each plug). In fact, AMD rates the 7950 right at 200 W. In comparison, the Radeon HD 7970’s power ceiling is 250 W, necessitating its eight- and six-pin power connectors.

A 10.5” PCB is extended out an additional half of an inch by a metal base plate and plastic shroud. So, plan accordingly when you pick a chassis. This card is fairly long.

As with the Radeon HD 7970, AMD employs a centrifugal fan mounted on one end of the Radeon HD 7950, which blows across the length of the card and exhausts heated air out the back of your chassis. This is the design we prefer. It wasn’t possible to cool the Radeon HD 6990 or GeForce GTX 590 the same way. In both examples, a center-mounted fan exhausted some air from a rear I/O slot and everything else was recirculated.

Because it relies on effective exhaust, one of the card’s two slots is grated for unrestricted air flow. The other slot is populated with four display outputs: one dual-link DVI connector, one full-sized HDMI port, and a pair of mini-DisplayPort outputs.

Board partners will almost certainly bundle a variety of adapters, so be sure you’re getting the components you need before making a purchase. The two Sapphire Radeon HD 7970s we bought came with DVI-to-VGA, mini-DisplayPort-to-DisplayPort, mini-DisplayPort-to-single-link DVI, and HDMI-to-DVI adapters. Meanwhile, the XFX R7950 Black Edition card we received only included an HDMI-to-DVI adapter.

More notable, though, is that all four outputs can be active at the same time, supporting extensive display configurations that you simply cannot achieve on a single Nvidia-based board.

Radeon HD 7950Radeon HD 7950Radeon HD 7970Radeon HD 7970

Tahiti Pro: Same GPU, But On A Diet

Radeon HD 7950 centers on the same 4.31 billion-transistor Tahiti GPU as AMD’s faster, more expensive flagship, manufactured on TSMC’s 28 nm node.

However, instead of sporting 32 Compute Units, this scaled-back model comes equipped with 28 Compute Units. As you know, each CU plays host to four Vector Units, each with 16 shaders, ALUs, Stream Processors, or whatever else you’d like to call them. That’s a total of 64 SPs per CU. A quick little multiplication (64*28) gives you a grand total of 1792 SPs on this chip.

And because each of those four missing CUs also included four texture units, that specification drops from 128 to 112.

Tahiti Pro: 28 Compute UnitsTahiti Pro: 28 Compute Units

To help differentiate the Radeon HD 7950 even further, AMD dials back its core clock rate to 800 MHz (down from 925 MHz on the reference Radeon HD 7970). Peak compute performance correspondingly drops to 2.87 TFLOPS from 3.79 TFLOPS.

The render back-ends are independent of the CUs, and AMD leaves all eight ROP partitions enabled, yielding up to 32 raster operations per clock cycle. Six 64-bit memory controllers feed the partitions through a crossbar. An aggregate 384-bit data path populated with 3 GB of GDDR5 memory operating at 1250 MHz adds up to 240 GB/s of bandwidth. That’s a slight drop from the Radeon HD 7970’s 264 GB/s, but still a very substantial increase over the Radeon HD 6970.


Radeon HD 7950
Radeon HD 7970
Radeon HD 6970
GeForce GTX 580
Stream processors
1792
20481536
512
Texture Units
112
128
9664
Full Color ROPs
32
32
3248
Graphics Clock
800 MHz
925 MHz880 MHz772 MHz
Texture Fillrate
89.6 Gtex/s
118.4 Gtex/s
84.5 Gtex/s49.4 Gtex/s
Memory Clock
1250 MHz
1375 MHz1375 MHz1002 MHz
Memory Bus
384-bit
384-bit256-bit384-bit
Memory Bandwidth240 GB/s
264 GB/s
160 GB/s192.4 GB/s
Graphics RAM
3 GB GDDR5
3 GB GDDR5
2 GB GDDR51.5 GB GDDR5
Die Size
365 mm2
365 mm2
389 mm2520 mm2
Transistors (Billion)
4.31
4.31
2.643
Process Technology
28 nm
28 nm40 nm
40 nm
Power Connectors
2 x 6-pin
1 x 8-pin, 1 x 6-pin1 x 8-pin, 1 x 6-pin
1 x 8-pin, 1 x 6-pin
Maximum Power
200 W
250 W
250 W
244 W
Price (Street)

$549
~$350
~$480
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Top Comments
  • 26 Hide
    bak0n , January 31, 2012 3:38 AM
    More good GPU news. Keep em coming!
  • 24 Hide
    hardcore_gamer , January 31, 2012 4:29 AM
    According to W1zzard's review, this card tops the Performance / Watt chart.
  • 22 Hide
    Anonymous , January 31, 2012 4:24 AM
    It beats the GTX580 one on one in most benchies and that's not taking into account the overclocking headroom these things have, they're also power friendlier and with XFX, cooler, quieter and expected to be cheaper so what's the problem? Me thinks me smell's NV fanboys!!
Other Comments
  • 26 Hide
    bak0n , January 31, 2012 3:38 AM
    More good GPU news. Keep em coming!
  • 21 Hide
    thesnappyfingers , January 31, 2012 4:02 AM
    stm I was thinking the same thing. But then agian it is still cheaper, more efficient compared to the gtx 580. Still, I am waiting it out till kepler.
  • 8 Hide
    Derbixrace , January 31, 2012 4:19 AM
    great value compared to the 7970 because you can OC it to be faster than it on stock voltage and even further with voltage tweaking ;) 
  • 6 Hide
    esrever , January 31, 2012 4:23 AM
    I'd love to have one once kepler comes and these drop in price. Im gonna start saving.
  • 22 Hide
    Anonymous , January 31, 2012 4:24 AM
    It beats the GTX580 one on one in most benchies and that's not taking into account the overclocking headroom these things have, they're also power friendlier and with XFX, cooler, quieter and expected to be cheaper so what's the problem? Me thinks me smell's NV fanboys!!
  • 24 Hide
    hardcore_gamer , January 31, 2012 4:29 AM
    According to W1zzard's review, this card tops the Performance / Watt chart.
  • 3 Hide
    primonatron , January 31, 2012 4:29 AM
    Are the Skyrim benchmarks on the v1.4 beta patch?

  • 9 Hide
    dragonsqrrl , January 31, 2012 4:29 AM
    rmpumper7950/7970 should be priced ~$50+ of 6950/6970 prices. So as it is now, if nvidia's gtx680 will be better than 7970 they will price it at >$600? That's a load of crock.

    Every rumor and leak I've seen so far on gk104 pricing seems to indicate otherwise...

    http://www.guru3d.com/news/nvidia-gk104-kepler-gpu-priced-at-299-230-/

    According to Nvidia's AIB partners the initial price set for the first gk104 based graphics card is $300. Of course this can go up or down based on the competition. Unfortunately, I have the feeling it'll be going up.
  • 3 Hide
    giovanni86 , January 31, 2012 4:43 AM
    This is all good news for the GPU market and for fans of ATI. Waiting on keplar from Nvidia, i buy into the marketing of "The way its meant to be played" =D hahahah. But great news, i love seeing my card get rocked. Competition is always great for pricing =D
  • -7 Hide
    msgun98 , January 31, 2012 4:52 AM
    lou007aIt beats the GTX580 one on one in most benchies and that's not taking into account the overclocking headroom these things have, they're also power friendlier and with XFX, cooler, quieter and expected to be cheaper so what's the problem? Me thinks me smell's NV fanboys!!


    Congratulations. The 7950 narrowly beats a year old card and costs the exact same. No thanks, I'll wait on Kepler and then decide what to get once AMD puts down the pipe and has to get real on their prices. And I'm a proud owner of a 4870.
  • 1 Hide
    giovanni86 , January 31, 2012 5:04 AM
    lou007aIt beats the GTX580 one on one in most benchies and that's not taking into account the overclocking headroom these things have, they're also power friendlier and with XFX, cooler, quieter and expected to be cheaper so what's the problem? Me thinks me smell's NV fanboys!!


    It does beat it, i can say it does.. My SC GTX580 was pulling around the same bandwidth as one they have here, i overclocked it and was getting almost 200GB's of bandwidth and was quite surprised i was able to push it and keep it like that with no trouble at all in any game i play and pretty much passed each stress test without any artifacts that i ran for hours. Headroom to OC differentiates from card to card, and nothing is guaranteed. But of course with 7950 im impressed it does very well even though the spec's on it look like it can run a marathon around the 580 with no trouble at all, but it does keep up with it and battle it out. I hope nvidia see's this as a threat and drops there price on the 580 so i can pick up another for around $400 =D Would make me very happy.
  • -1 Hide
    de5_Roy , January 31, 2012 5:22 AM
    nice.
    7950's power consumption in single and cfx mode are quite impressive.
    i'll compare them to kepler when they come out and get tested.. right now, gcn high end looks much better than fermi high end (gpu compute, power efficiency etc).
    amd's driver support seems inconsistent as usual... hopefully more mature drivers will bring out even more performance out of the gcn cards.
  • 4 Hide
    kvarta , January 31, 2012 5:23 AM
    That's strange, in other sites says that card is "...relatively inaudible...". Example:
    http://www.guru3d.com/article/his-radeon-hd-7950-review/25
    As always good job Chris.
  • -2 Hide
    dragonsqrrl , January 31, 2012 5:45 AM
    kvartaThat's strange, in other sites says that card is "...relatively inaudible...". Example:http://www.guru3d.com/article/his- [...] -review/25As always good job Chris.

    The editors at Guru3D perform their noise tests differently than most other sites. The cards are placed in a closed case and measurements are taken from a few feet back. These editors are also either partially deaf, or they just don't give a damn about excessive system noise. Honestly, I don't think they've ever knocked a card for being too loud, even the HD6990.
  • 13 Hide
    tlmck , January 31, 2012 5:55 AM
    Bring on the mid range!
  • 10 Hide
    jezus53 , January 31, 2012 6:07 AM
    msgun98Congratulations. The 7950 narrowly beats a year old card and costs the exact same. No thanks, I'll wait on Kepler and then decide what to get once AMD puts down the pipe and has to get real on their prices. And I'm a proud owner of a 4870.


    You are aware that the 7950 is not supposed to directly compete with the 580, right? The 7970 is supposed to beat the 580 and the 7950 is supposed to beat the 570. Just like how the 6970 is supposed to compete with the 580 and the 6950 is supposed to compete with the 570. The shear fact that the non flagship GPU beats the flagship GPU of your competitor is pretty awesome.
  • 5 Hide
    lordstormdragon , January 31, 2012 6:15 AM
    jezus53The shear fact that the non flagship GPU beats the flagship GPU of your competitor is pretty awesome.


    AMD has had plenty of time to play catch-up. It's not "pretty awesome" they leap-frogged Nvidia once again. It's a calculated move on AMD's part, for certain. A good one, but "pretty awesome" is very far from "standard dual-monopoly leap-frogging that's gone on since both companies started". Relax.

    That said, I DO celebrate and find it ironic that AMDs 7950 is as flag-shippy whoop-ass as Nvidia's 7950 was in its day! I'm looking at my dead beast here right now. Miss you, 7950GT. I... I loved you. I can say that, now.


  • 4 Hide
    stm1185 , January 31, 2012 6:22 AM
    jezus53You are aware that the 7950 is not supposed to directly compete with the 580, right? The 7970 is supposed to beat the 580 and the 7950 is supposed to beat the 570. Just like how the 6970 is supposed to compete with the 580 and the 6950 is supposed to compete with the 570. The shear fact that the non flagship GPU beats the flagship GPU of your competitor is pretty awesome.


    It is not pretty awesome that your next gen part that you priced slightly below the competitors flagship last gen part outperforms it in some tests. That is to be excepted. The 7950 is not against a gtx 570, its against a gtx670 which is not out yet, and will probably be replaced around the same price point as a 570 with a large performance increase over it, making buying a $450 7950 retarded; as such the 7950 will then get dropped to where the 6950 is now to be competitive.

    Anyone who buys a 7950 before AMD at $450 is a chump. 30%+ price drop as soon as Nvidia releases its next gen.
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