Sapphire Radeon HD 4850 X2 dual-GPU graphics card
One card, two very fast graphics chips
Review The thinking behind the ATI Radeon HD 4870 X2 seems quite clear. One 4870 and a bunch of GDDR 5 is the basis for a decent graphics card that costs £200-240 but lacks the grunt to take on the GeForce GTX 280. Join two 4870s together on a single card and you have the "fastest gaming graphics card in the world", allegedly.
As an added bonus the £399 price is marginally cheaper than buying two individual 4870s.
Sapphire's HD 4850 X2: four DVI-I ports, anyone?
The Radeon HD 4850 X2 follows the same blueprint by joining two 4850s on a single graphics card, but it’s a different proposition. The 4870 X2 was manufactured by AMD and marketed by its partners, while the 4850 X2 is made by the partners themselves. To date, this Sapphire card is the only 4850 X2 we’ve seen and we suspect that the strength of the dollar will kill off plans by some other companies to follow it.
The problem is that a 4850 X2 with 1GB of DDR 3 will sell for the equivalent of $369. The 2GB version is $419. In a sane and righteous world, we’d be looking at UK prices of £219 and £249, respectively, that compare quite favourably with a 1GB 4850 at £135 and a 2GB model at £165. Unfortunately, however, you can expect the two Sapphires to go on sale at £270 and £317, which is the same price as two individual 4850 cards.
There's a superficial similarity between the Sapphire 4850 X2, AMD's 4870 X2 and Nvidia's GeForce GTX 280: all three cards are double-slot designs that are very long. The 4870 X2 and GTX 280 measure 267mm in length, while the Sapphire is a tad longer, at 285mm. The Sapphire design department has clearly been hard at work, and while the 4870 X2 has a humongous weight of 1218g the Sapphire comes in at a sprightly 764g. To put that in context the GeForce GTX 280 weighs 908g.
Two fans make card light
The GTX 280 and 4870 X2 each use a single cylindrical 70mm fan that blows air the length of the card until the hot air exhausts through the vented bracket. In the case of the 4870 X2, the heatsink is a slab of copper, which explains the weight of the card, but Sapphire has chosen to install an aluminium heatsink on each of the 4850 GPUs, with a pair of 75mm fans to keep everything cool. They are the sort of coolers that you use on a CPU. The heat exhausts inside the PC case, so you may well need to consider some additional case cooling as the Sapphire draws 165W in Windows and 280W during a gaming session.
The black shroud you see in the photos is a piece of curved aluminium that pretties up the card and helps to keep cables out of the fans.
The two 4870 X2 bars in the charts have the same description, I assume the second is overclocked? However some of the benchmark/timing results for various cards are clearly spurious compared to their overall performance differentials. I suggest you revisit this.
ATI Linux driver support has improved dramatically from several years ago. I have a number of machines with ATI cards (3870, 24-something, a 690 based uATX board with integrated graphics and a Dell with embedded ATI graphics). The ATI installer is pretty bulletproof and the performance is good. Not at all like back in the days of the 9700. I used to worry about using ATI with Linux: I do not anymore.
I have read that neither ATI nor Nvidia supports CF/SLI under Linux. I don't know if it is true. Can anyone confirm or refute?
The driver is built around a kernel module and if the kernel is updated then the graphics driver must be reinstalled, which is a pain. But Nvidia is the same in this regard.
FWIW, ATI's CAL or Stream Computing SDK also runs on Linux now. As much as I have played with it, it seems to work well (I have not had as much experience with CAL as with CUDA though.)
AFAIK - as of about 8 months ago - neither CAL nor CUDA will use both GPUs if the GPUs are in Crossfire/SLI mode. This would be a problem with ATI or Nvidia. If the cards are not paired up then both are available - I've verified this with an Nvidia 8600 and 8800 in the same box, and it is what ATI says in it's docs.
Looks as if
ATI may finally be getting their act together. When I got to rebuild (my now three year old) game rig I may have to take a look at their cards in comparison to nVidia, thanks.
165W in Windows?
Quick Linux compatibility check?
Given that you've probably got quite a few Linux users in your readership, would it be possible to do a brief check of hardware like this on Linux?
Nvidia kit generally has very good OpenGL support, and is very good with simulators like X-Plane, Silent Wings or FlightGear. It would be nice if you could see if the ATI/AMD kit is beginning to improve the Linux driver support since the two companies merged.
It would be nice if you could do a more in-depth report than "yes, it works and it looks nice", but even thats better than nothing :-)