AMD's Radeon HD 4870 X2 - Testing the Multi-GPU Waters
by Anand Lal Shimpi & Derek Wilson on August 12, 2008 12:00 AM EST- Posted in
- GPUs
Today is all about the Radeon HD 4870 X2, the same card we previewed last month but AMD is quietly announcing a few other products alongside it. The 4870 X2, internally referred to as R700, is a pair of RV770 GPUs on a single card - effectively a single-card, Radeon HD 4870 CrossFire (hence the X2 moniker). Like previous X2 cards, the 4870 X2 appears to the user and the driver as a single card and all of the CrossFire magic happens behind the scenes.
| ATI Radeon HD 4870 X2 | ATI Radeon HD 4870 | ATI Radeon HD 4850 | |
| Stream Processors | 800 x 2 | 800 | 800 |
| Texture Units | 40 x 2 | 40 | 40 |
| ROPs | 16 x 2 | 16 | 16 |
| Core Clock | 750MHz | 750MHz | 625MHz |
| Memory Clock | 900MHz (3600MHz data rate) GDDR5 | 900MHz (3600MHz data rate) GDDR5 | 993MHz (1986MHz data rate) GDDR3 |
| Memory Bus Width | 256-bit x 2 | 256-bit | 256-bit |
| Frame Buffer | 1GB x 2 | 512MB | 512MB |
| Transistor Count | 956M x 2 | 956M | 956M |
| Manufacturing Process | TSMC 55nm | TSMC 55nm | TSMC 55nm |
| Price Point | $549 | $299 | $199 |
The benefit of single-card CrossFire is of course that you can use this single card on any platform, not just ones that explicitly support CF. Since CrossFire is supported on both Intel chipsets and AMD chipsets, it's a bit more flexible than SLI and the need for single-card CF isn't nearly as great as the need for single-card SLI.
Unlike most single-card multi-GPU solutions, the 4870 X2 is literally two Radeon HD 4870s on a single card. The clock speeds, both core and memory, are identical and this thing should perform like a pair of 4870s (which is pretty quick if you have forgotten). The only difference here is that while the standard Radeon HD 4870 ships with 512MB of GDDR5 memory, each RV770 on a X2 gets a full 1GB of GDDR5 for a total of 2GB per card.
...which leads us nicely into some of AMD's other products that will be coming out in the next month or so. There will be 1GB versions of both the Radeon HD 4870 and Radeon HD 4850.
Then at $399 we'll see a Radeon HD 4850 X2, which as you can probably guess is a pair of Radeon HD 4850 GPUs on a single card, but with 2GB of GDDR3 and not GDDR5 like the 4870 X2. As interesting as all of these cards are, we only have the 4870 X2 for you today, the rest will have to wait for another time. But it is worth noting that if you are interested in buying a Radeon HD 4870/4850 and keeping it for a while, you may want to wait for the 1GB versions as they should give you a bit more longevity.
Enough with being distracted by AMD's product lineup, let's talk about the competition.
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pattycake0147 - Tuesday, August 12, 2008 - link
I've noticed the same bias recently. I've only been a member for a little over a year now and even in the short time the site has gone downhill.sweetsauce - Tuesday, August 12, 2008 - link
Translation: I like ATI and you don't so im going to bitch. Even though my name is tech guy, i obviously have ovaries. I'm going to go cry now on ATI's behalf.jnmfox - Tuesday, August 12, 2008 - link
Get over yourself. Pointing out facts isn't taking pot-shots.This is just what I was looking for in a review of the X2. The numbers tell the story. In the majority of cases the X2 isn't worth it, and until AMD & NVIDIA get proper hardware implementation of multi-GPU solutions it will most continue to be the case.
To little performance increase for the large increase is cost.
skiboysteve - Tuesday, August 12, 2008 - link
i completely agree with anand on this article. the lack of innovation from a company supposedly focusing on multi chip solutions is stupidalthough yes, it is really fast.
and why cant they clock it lower at idle?
astrodemoniac - Tuesday, August 12, 2008 - link
... reviews I have ever seen here @ Anands. I am extremely disappointed with this so called "Review" ... hell, I have seen PREVIEWS that would put it to shame.Oh, and what in the hell did AMD do to you that you're so obviously pissed off at them?... are you annoyed they didn't give you preferential treatment to release the review earlier? man just go back to the unbiased reviews, we're buying graphic cards, not brands.
It's like the guys writing the reviews are not gamers any more o_0
/rant
Halley - Wednesday, August 13, 2008 - link
It's no secret that AnandTech is "managed by Intel" as a user put it. Of course every one must have some source of income to support their families and themselves but it's pathetic to show such blatant biasedness.TheDoc9 - Tuesday, August 12, 2008 - link
Anandtech isn't about gaming anymore, it's about photography and home theater. And the occasional newest intel extreem cpu.I think Dailytech and the forums carry Anandtech these days...
DigitalFreak - Tuesday, August 12, 2008 - link
"AMD decided that since there's relatively no performance increase yet there's an increase in power consumption and board costs that it would make more sense to leave the feature disabled. "In other words, it's broken in hardware and we couldn't get it working, so we "disabled" it.
NullSubroutine - Tuesday, August 12, 2008 - link
You didn't even include test system specs or driver versions.CreasianDevaili - Tuesday, August 12, 2008 - link
I wanted to know why you didnt retest the 4870CF setup when you obviously had some issues with it before in GRID. I noticed the 280gtx setup was retested which resulted in higher FPS. I feel that after running the game at 2560x1600 on my FW900 and also from other reviews that you had a issue with crossfire not working at that resolution. The single 4870 shouldnt be getting better FPS by that degree at 2560x1600 because it also has 512mb of vram.So I just wanted to know why the 280gtx was special enough to retest when this review was about the 4870X2. If it is to show a good comparison then why wasnt the 4870CF, which many have and want to see, not retested as well.