A peek at the Radeon HD 5870 X2

Robert Hallock 28 Sep, 2009 at 9:49pm ET Article published in Tech

For some time now we have believed that the as yet-unreleased Radeon HD 5870 X2 (codename “Hemlock”) was to be a dual-GPU/single-PCB part. These suspicions were confirmed this weekend thanks to an AMD-run DirectX 11 forum which had the GPU on hand.

As can be seen from the images, the 5870 X2 uses a 6+8-pin connector configuration for power. Secondly, we’ve estimated the length of the card at 10.7 inches (271.51mm) based on the length of the PCI Express x16 connector.

Outstanding unconfirmed rumors include:

A TDP of 376W (2*188W for HD 5870);
A November launch date and
A $599 MSRP

While we’ll place our bets on a November launch as well, the Radeon HD 5000 series’ launch has lead us to believe that a ~293W TDP and a $579 MSRP are more likely.

For more information on features the Radeon HD 5870 X2 will offer, Icrontic has published articles which detail the Radeon HD 5870 GPU and DirectX 11.

Comments

28 Sep 2009 ~ 10:14pm Cliff_Forster First, Wow!

Is there a case on earth that will fit that thing? Might be an issue?
28 Sep 2009 ~ 10:14pm lordbean Now there's a little slice of sexy hardware.

Want.
28 Sep 2009 ~ 10:17pm UPSLynx Cliff - my chassis (and probably Bindle Stick's new build)

A TDP of 376W (2*188W for HD 5870);

HHHNNNNNNNGGGGGGGG
!!!

DO WANT, but the power consumption would make me think otherwise. That's a LOT of juice. Even at the more moderate thought of ~293w TDP, ...eff. powerbills will skyrocket. Turn on the PC, play a game, brownout the house. Heck, if you live in California, play a game, brownout the city.
28 Sep 2009 ~ 10:20pm Cliff_Forster Could you imagine stacking a pair in crossfire?? I want to do that so bad, $1,200 is a little prohibitive though. Damnit fiscal responsibility!!
28 Sep 2009 ~ 11:09pm lordbean Much as that card makes me drool, the best I'll probably end up with is likely a 5870 paired with a 5850. Since you CAN put different models together, it makes it hard for me personally to justify having 2 of the more expensive one, especially on my budget.
28 Sep 2009 ~ 11:44pm Cliff_Forster Lordbean, Don't mix em, the 5850 will limit the 5870 and you will just end up for the performance of two 5850's anyway.

I'm actually leaning t words buying a single 5850 for now, selling my old card it should only be about a $150 net expense while offering me about a 40% performance gain but most importantly the new features. I'll smack a 2nd board on when practical.

For $259 the 5850 is the best deal of the bunch and you really are not giving up that much.
29 Sep 2009 ~ 11:09am lordbean

Cliff_Forster wrote:

Lordbean, Don't mix em, the 5850 will limit the 5870 and you will just end up for the performance of two 5850's anyway.

Actually, unless the 5000 series has a behavior change in this regard, it won't limit the 5870 at all. The 4000 generation crossfire is not limited by the slower card, and I've confirmed this for myself... I ran my primary HD4850 at full speed and my slave 4850 at half clock, and it made zero performance difference in games, benchmarks, etc.
29 Sep 2009 ~ 11:18am Cliff_Forster

lordbean wrote:

Actually, unless the 5000 series has a behavior change in this regard, it won't limit the 5870 at all. The 4000 generation crossfire is not limited by the slower card, and I've confirmed this for myself... I ran my primary HD4850 at full speed and my slave 4850 at half clock, and it made zero performance difference in games, benchmarks, etc.

I never understood it to be that way? I always thought the lesser card was the limiting factor in a crossfire setup? In other words it would clock to the lower variable, as well as limit the total number of stream processors available. Say you pair a 4870 with a 4830 each card will run 640 streams clocked down to the 4830's speed, or so I thought?

I'd love to get some performance benefit by slapping a 5850 on the board with the 4870 I have, I just figure I will loose the DX11 features and I will be limited, in short, the 5850 will only perform as well as a 2nd 4870?
29 Sep 2009 ~ 11:20am lordbean I don't recall where I found the article on this, but that analysis isn't true, and AMD themselves has even said so. The only thing you can't mix and match on 4000 series cards is RAM sizes - if you stick a 4870 1GB with a 4850 512MB, the 4870 will only use 512MB of its own RAM, but it does not clock down to match the 4850's clocks or stream processors.
29 Sep 2009 ~ 11:23am mirage Ray Adams agrees with Cliff.
http://forums.guru3d.com/showthread.php?t=275077&page=34
29 Sep 2009 ~ 11:31am lordbean AMD does not.

http://forums.amd.com/game/messageview.cfm?catid=262&threadid=115144&highlight_key=y&keyword1=mixed%20crossfire

Scroll down to the moderator's post.
29 Sep 2009 ~ 11:37am mirage Sorry, Ray Adams is "the" authority I believe instead of "a" moderator.
29 Sep 2009 ~ 11:37am Thrax Cliff, EDIT: Daedalus685, and Ray Adams are incorrect.

Putting two disparate cards from the same family into a CF configuration will only limit total memory capacity to that of the board with the most VRAM (e.g. 512+1024 = 1024 in CF). In all other ways, both cards will operate at their full capacity.
29 Sep 2009 ~ 11:39am lordbean At the end of the day, this is still more about picking who to believe than anything... I'm going to re-run the benchmarks on my Phenom II rig using both cards at full speed, and then with the slave 4850 downclocked. This should give more definitive answers to the question. I realize the number of stream processors is going to be the same, but by forcing asynchronous clocks I at least should be throwing the primary card out of whack, if ray adams is correct.

Edit - typing while Thrax posted. Appreciate that I'm not alone in this.
29 Sep 2009 ~ 11:43am Cliff_Forster

Thrax wrote:

Cliff, EDIT: Daedalus685, and Ray Adams are incorrect.

Putting two disparate cards from the same family into a CF configuration will only limit total memory capacity to that of the board with the most VRAM (e.g. 512+1024 = 1024 in CF). In all other ways, both cards will operate at their full capacity.

Well, I have a 4870 with 1024 Ram DDR5, so not much of a limiting issue there.

Hypatheticly, I get a 5870 board, slap it on, am I running 1600+800 = 2400 total stream processors? Will my system setup be capable of running DX11? Will it run DX11 while leveraging the assets of both cards?
29 Sep 2009 ~ 11:45am Thrax You cannot mix card families. A 3xxx cannot be paired with a 4xxx or 5xxx, nor can a 4xxx be paired with a 5xxx. The drivers will not enable CrossFireX.
29 Sep 2009 ~ 11:46am lordbean

Cliff_Forster wrote:

Well, I have a 4870 with 1024 Ram DDR5, so not much of a limiting issue there.

Hypatheticly, I get a 5870 board, slap it on, am I running 1600+800 = 2400 total stream processors? Will my system setup be capable of running DX11? Will it run DX11 while leveraging the assets of both cards?

No to all questions. You cannot mix and match different generations of cards - AMD has also said that. I wouldn't even try it myself due to different DirectX versions.

They have previously stated that matching 4xxx with 4xxx is fine, 3xxx with 3xxx is fine, etc, but you can't put a 3xxx with a 4xxx or any other such combination and expect it to work, because it won't.
29 Sep 2009 ~ 11:49am Cliff_Forster Very well. I figured as much, but there is obviously some confusion about the system. Perhaps Hyrdra will remedy this someday?
29 Sep 2009 ~ 11:54am lordbean I still intend to go through with my above post when I get home from work. I'm going to run a testing battery on my 4850s using both at full speed, and then the slave at half speed, and then both at half speed for good measure, and see what I turn up. That should help demonstrate the workings of the technology a little better.
29 Sep 2009 ~ 11:54am mirage

Thrax wrote:

Cliff, EDIT: Daedalus685, and Ray Adams are incorrect.

Putting two disparate cards from the same family into a CF configuration will only limit total memory capacity to that of the board with the most VRAM (e.g. 512+1024 = 1024 in CF). In all other ways, both cards will operate at their full capacity.

Okay, I believe Thrax too

How efficient the driver does load balancing between the two different cards? Can both cards be used at full capacity? Or the faster card idles a little to wait for the slower card?
29 Sep 2009 ~ 12:02pm mirage Nevermind, I found the answer at the link below. Seems pretty efficient load balancing to me. Kudos to ATI.

http://www.legitreviews.com/article/663/1/
29 Sep 2009 ~ 12:07pm Thrax CrossFireX scalability really depends on the game, and the API (DirectX vs. OpenGL). DirectX scaling has received the most work, as the majority of today's titles are based on DirectX. Secondly, the X2 cards typically scale better than paired cards... There are many reasons for this, but they're immaterial to the question.

Given these caveats/exceptions, a performance breakdown of the 4xxx series would look something like this:

4890 CrossFire
4870 X2
4870 CrossFire
4870 + 4850 CrossFire
4850 X2
4850 CrossFire
4890
4870
4850

As you can see, the 4870+4850 comes in ahead of a dual-GPU 4850 solution, but behind a CF 4870 array.

In all the circumstances described above, the cards are working at their maximum capacity with respect to the scaling offered by the title.
29 Sep 2009 ~ 12:15pm mirage Thanks for the reply. I am amazed with ATI's work on CrossFireX. I am thinking about the cluster computers we run, I can not imagine how balancing would work with different CPUs. But you are right it must depend on the parallelism of the task, the particular game in Crossfire case.
29 Sep 2009 ~ 1:04pm lordbean

mirage wrote:

Nevermind, I found the answer at the link below. Seems pretty efficient load balancing to me. Kudos to ATI.

http://www.legitreviews.com/article/663/1/

Hmm. Seems that article already did my intended work for me.

I'm still likely going to try a 5870/5850 configuration eventually, so we'll see if the technology works as well in the 5000 series.