Benchmarking AMD's 768-Shader Pitcairn: Not For Public Consumption

A Look At The Tech Specs

We can’t help but wonder why AMD leaves such a large gap in its line-up instead of plugging it with a card that would practically be without a direct competitor. Even overclocking our Radeon HD 7770 to 1.15 GHz doesn't reliably push it to that half-way point between a stock 7770 and 7850. So, filling the void by simply increasing the clock speed of an existing product is not an option for AMD. How about tacking on a few more shader units to a Cape Verde GPU? That seems just as unlikely since it requires a redesign.

Now, we could speculate that the yields for AMD’s Pitcairn chips are apparently so good that there simply aren’t enough partially-defective chips to “harvest” and recycle into a card that slots in between the 7700 and 7800 families (a move we’ve seen from AMD and other companies in the past). AMD's Radeon HD 5830 and Nvidia's GeForce GTX 560 TI 448 Core are good examples.

On the other hand, it's just good business to address an audience looking for a better card at a certain price point, even if it means artificially paring down an otherwise healthy existing product. Again, that’s something we’ve seen in the past on a number of occasions.

The engineering sample itself.The engineering sample itself.

Here’s how our engineering sample would fit into AMD’s existing portfolio of GCN-based cards:


Radeon HD 7770
Radeon HD 7850
768-Shader ES
Radeon HD 7850
Radeon HD 7870
Stream Processors
640
768
1024
1280
Texture Units
40
64
64
80
Full Color ROPs
16
32
32
32
GPU CLock
1000 MHz
860 MHz
860 MHz1000 MHz
Texture Fillrate
40 Gtex/s
41.3 Gtex/s
55 Gtex/s
80 Gtex/s
Memory Clock
1125 MHz
1200 MHz
1200 MHz
1200 MHz
Memory Interface
128-bit
256-bit
256-bit
256-bit
Memory Bandwidth
72 GB/s
153.6 GB/s153.6 GB/s
153.6 GB/s
Video-RAM
1 GB GDDR5
2 GB GDDR52 GB GDDR52 GB GDDR5
Transistors (Billion)
1.5
2.82.8
2.8
Manufacturing Process
28 nm
28 nm28 nm
28 nm
Aux Power
1 x 6-pin1 x 6-pin1 x 6-pin
2 x 6-pin
Power Consumption (max. measured)
80 W
120 Watt*
130 W175 W
Market Price
(Newegg, May 08, 2012)
~$149+
~$200+ (If we got our way)
~$250+
~$330+

*Note: This is an engineering sample, not a final GPU.

This is what the card looks like without its cooler.This is what the card looks like without its cooler.

Actually, the tech specs represent a pretty plausible starting point for our analysis, since a 25 percent reduction in shader units should translate to between 20 and 25 percent less performance, depending on the workload. Since we’re dealing with an engineering sample on a prototype board intended to bring up full Radeon HD 7850 cards, attributes like power consumption and heat don't bear the weight they would if we were looking at a piece of production hardware. Let’s not forget, the express purpose of the card we have in-house is to give board partners a way to tweak and improve their designs, bringing down power consumption and optimizing cooling on final boards. With that said, we don’t think AMD has anything to worry about, based on the numbers we got from our engineering sample. For what it is, the board returned completely acceptable results.

A view from below.A view from below.

Even in its prototype stage, our review sample does not disappoint. So, without further ado, let’s get cracking on those benchmarks!

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71 comments
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    Top Comments
  • woe96
    i want one, that a amazing place in performance and probably only be $200
    23
  • borden5
    oh man that single slot would be really nice for people who wanted small factor rig
    22
  • weatherdude
    This card performs great and a 1 GiB version selling at ~$200 would fill in a very large gap in the market. It would only make sense if AMD is cooking up something they'll likely call a 7830 to do just that. I guess though it would differ from this engineering sample if they're so insistent that they aren't bringing it to market. Maybe it'll have less texture units or ROPs.

    Still this card with 1 GiB at ~$200 would be pretty sweet AMD *nudge* *nudge*.
    20
  • Other Comments
  • woe96
    i want one, that a amazing place in performance and probably only be $200
    23
  • s3anister
    I would never buy this card for myself but I would find myself recommending a 1GB model, like you mentioned, to family and friends. If the price is right AMD could have a great mid range card.
    15
  • wolley74
    while a nice card, the 6850 is incredibly close and nearly $60 cheaper, the only thing is it does consume more power
    -9
  • borden5
    oh man that single slot would be really nice for people who wanted small factor rig
    22
  • slomo4sho
    Wouldn't 2 7750s in crossfire perform better than this rig and also consume less power at the ~$200 price point?
    -8
  • erraticfocus
    Slomo4shOWouldn't 2 7750s in crossfire perform better than this rig and also consume less power at the ~$200 price point?


    Maybe, depending on your local market, but the single slot and price point is the whole point to this...
    17
  • Anonymous
    Say hello to the AMD HD Radeon 7790.
    -1
  • pwnorbpwnd
    This card would be an AMAZING pick for an HTPC, Single slot, Low power, 2gb DDR3 for HDTV's, not to say 1gb wouldn't be okay. But really AMD, do it up! All of this positive feedback is great reason to make a crippled 7850!
    15
  • weatherdude
    This card performs great and a 1 GiB version selling at ~$200 would fill in a very large gap in the market. It would only make sense if AMD is cooking up something they'll likely call a 7830 to do just that. I guess though it would differ from this engineering sample if they're so insistent that they aren't bringing it to market. Maybe it'll have less texture units or ROPs.

    Still this card with 1 GiB at ~$200 would be pretty sweet AMD *nudge* *nudge*.
    20
  • Anonymous
    Doesn't the 7770 have 40 Texture Units and not 14?
    6
  • atikkur
    now bring the game..
    1
  • blazorthon
    A "7830" with 1GB of VRAM priced to compete with the 6870 or 6930 (if you have that in your country, the USA doesn't) 1GB cards would be great. If anyone wants a new card between the 7770 and 7850 in performance (basically, between a just short of a 6850 and just short of a 6970), then they're screwed because there is no middle point. They have no choice other than buying an old 6870, 6930, or 6950.

    With a 1GB model at $185 to $195 and a 2GB model (2GB is far better than 1GB for Crossfire setups at higher resolutions/quality/AA/AF) at $210 to $220 would be good. Also, 7830 is the best name for this, at least in my opinion. All that would need to be done is bringing down the power usage a little (need is a strong word for this, that it is lower than the 7850 is still a great improvement over the 5830 and 6790 fiascoes). I would like to see a 100 to 110 watt TDP, rather than a 120w TDP (sure, TDP does not equal power usage, but still). Even without doing that, it still uses less power than the 6870, so it's acceptable. However, if Nvidia makes a competing card (looks like they will), then Nvidia would probably undercut it by at least 15 to 20w.

    Regardless, come on AMD, release this as a 7830 or something such as that! It's a great card and it fills a market that is almost desperate for a refresh!

    NivalisSay hello to the AMD HD Radeon 7790.


    7830.
    7
  • x3style
    Give single slot card so we can revigorate our minimalistic solutions with extra power for when diablo III arives.
    4
  • blazorthon
    wolley74while a nice card, the 6850 is incredibly close and nearly $60 cheaper, the only thing is it does consume more power


    You mean the 6870, not the 6850. If more games were included, we would see the 6870 closer to this hypothetical 7830 most of the time. Keep in mind that Tom's tested a 2GB model, so you would have to compare it's price against the 6870 2GB for a fair comparison, not the 6870 1GB.
    1
  • manu 11
    want one, cant afford the 7850! $160 should do it justice.
    9
  • Rattengesicht
    Do it AMD ! You know you want to ;-)
    10
  • Maximus_Delta
    I really like this sort of investigative journalism. Two thumbs up.
    14
  • Darkerson
    I guess we'll just have to wait and see if they change their mind and release it eventually. Would be a nifty little card with a more affordable price tag.
    1
  • esrever
    Anyone else notice that the 7970 and the 680 are trading blows? And it seems that they are pretty even?
    10
  • Allan_01
    this should me HD7790
    -4