ATI's X8xx CrossFire Graphics Arrive
by Derek Wilson on September 26, 2005 1:00 PM EST- Posted in
- GPUs
Hardware and Power
The components that go into a CrossFire system consist of the CrossFire master card, a slave card, a CrossFire dongle, and a motherboard with more than 1 PCI Express x16 slot. Here's the run down of our test system:AMD Athlon 64 FX-55
ATI Radeon Xpress 200 CrossFire motherboard
1GB DDR400 2:2:2:8 RAM
120GB Seagate 7200.7 HD
OCZ Powerstream 600W PSU
The CrossFire master card is basically an X850 XT with the addition of a Xilinx FPGA (for the compositing engine) and a TMDS receiver for taking input from the slave card. Instead of 2 DVI-D ports, the CrossFire master card makes use of a high speed DMS port. This connects to one port of the CrossFire dongle and takes the slave card input as well as providing the output to the monitor.
Other than that, the CrossFire card looks just like any other X850 XT out there.
The CrossFire design is fundamentally different than NVIDIA's SLI. CrossFire uses an external compositing engine while NVIDIA's is built into the GPU. ATI handles communication via TMDS output from the slave card's framebuffer, while NVIDIA built a chip to chip communications protocol for multi-GPU operation. Both vendors offer extended antialiasing modes, but ATI offers an additional rendering mode called SuperTiling which cuts each scene up into a checkerboard pattern for rendering.
On both solutions, Alternate Frame Rendering (AFR) is the fastest mode, as this is the only mode that also accelerates geometry processing. In order to learn more about the details of how CrossFire works, please check out our previous article on the subject.
As for the stress all this hardware puts on a system when it's in action, here's a comparisons of idle and load power (under Splinter Cell: Chaos Theory). Power is measured at the wall before the PSU.
While the idle power draw is slightly lower than 7800 GT SLI, the load power is the highest of any of the measured setups. 7800 GTX SLI would be higher still, but X850 XT PE Crossfire is really closer to the 6800 Ultra SLI or 7800 GT SLI, so it's not a fair comparison. We'll have to wait for R5xx and Crossfire before we can get a good idea of how Crossfire competes with 7800 GTX SLI.
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davecason - Tuesday, September 27, 2005 - link
http://www.anandtech.com/video/showdoc.aspx?i=2541...">http://www.anandtech.com/video/showdoc.aspx?i=2541...The word "us" should be "use" in this paragraph:
The CrossFire master card is basically an X850 XT with the addition of a Xilinx FPGA (for the compositing engine) and a TMDS receiver for taking input from the slave card. Instead of 2 DVI-D ports, the CrossFire master card makes us of a high speed DMS port. This connects to one port of the CrossFire dongle and takes the slave card input as well as providing the output to the monitor.
JarredWalton - Tuesday, September 27, 2005 - link
Fixed. I think that was a minor edit by me where I fixed one error and created another. Hahaha....Wesley Fink - Monday, September 26, 2005 - link
We will be posting an in-depth review of the ATI Crossfire AMD motherboard tomorrow. One thing no site has really talked about is what a great overclocker the ATI Crossfire AMD has become. The Reference Board has the best Enthusiast level options and controls I have EVER seen on a Reference Board, the overclocking performance is outstanding, and DFI promises they will deliver the same or better in the next few weeks in their own Crossfire AMD board.Another unmentioned biggie for me is the fact that the Crossfire X850 Master Card works just fine as a standalone X850 graphics card. If you have to buy a Master Card for Crossfire I think it's important to know you can use it ALONE as an X850 card when the next hot generation graphics comes along - it's not just an investment you have to throw away.
Derek talks a bit about how the next generation graphics fixes some of his concerns about Crossfire as a TODAY purchase. His comments should make more sense in that light, and they will certainly be clearer in the next couple of weeks when X1800 launches. Just keep in mind that the same Crossfire AMD motherboard will be used with X1800 and that the motherboard also works great with an nVidia 7800GTX and any other single nVidia or ATI graphics card right now.
michal1980 - Tuesday, September 27, 2005 - link
i have to say nice numbers by ati, buti mean who in the right mind is buying a 500 dollar x850 card, a 150-200 dollar mobo,
just to get crossfire, when in 1 week or so the x520 is supposd to come out. which by the way does not appear to have any menition of crossfire support. and while true you do not have to buy the same 2 cards for crossfire to work. the 2nd master card you buy costs you 100 bucks more. phhff. sorry. the whole sli/crossfire thing really doesn't make much sense unless you are always buying at the release of the tech. i.e. when the gtx gets released u buy 2.
but why would you buy into a crossfire setup now? when the next ati cards are coming out. if there similar to the nivida one. getting 2 x800s, is like roughly spending the money on 2 6600gts, when you could for the money buy the never, and overall better 1 card solution in a 7800gtx for the same money.
or a new x520, for the same money, i'd pass on getting old tech up to speed when new stuff is/will be here soon
michal1980 - Tuesday, September 27, 2005 - link
also if u do compare the 6800ultra vs the x850, the only game the ati car wins in is in hl2. go figure, a game they basicaly wrote for there hardware with the help of gabe 'i will delay this game till ati is ready'DerekWilson - Tuesday, September 27, 2005 - link
heh ... ATI was very unhappy with Valve's launch slip. They sank a lot of money into the HL2 bundle and launch efforts for a time frame that was a year before the game actually came along.waldo - Monday, September 26, 2005 - link
So, like most people on this forum, I read both here and at Tom's Hardware...and it is amazing to me the discrepancies in the writings of the articles. I was hoping you could clarify.1. Are they just bought out by ATI, or are you guys just bought out by NVIDIA?
1a. The conclusions drawn seemed to be in the face of each other. You are dead set against, and they are seeming for ATI's crossfire. This isn't fashion, or poetry, or a film, where you just go by what you like. There are frame rates, quality of picture, etc....why are they so different?
2. It appears that the benchmarks on Tom's are slightly different in comparison to yours, in that it shows the X850 crossfire doing slightly better than the 7800 SLI configuration in several instances.
3. Tom's foxused more on the notion that you don't need two of the exact same card. Based on your article, it is your opinion that you go 7800 SLI, or single wiht hopes of 7800 SLI later, rather than x850 now, and then the addition of R520 later? It would be helpful to have some benchies of mixed card situations.
I realize that it seems attacking, and really I posted here because I like Anandtech better than Tom's but I respect both as the best resources on the net for technology reviews, but it just seems odd that the two top sites out there come down on completely different sides of the fence.
Thanks
Frallan - Tuesday, September 27, 2005 - link
THG!Well as it seems THG has in the last two year gone from beeing a "not-so-good" hardwaresite (please buy it back Thomas) to currently beeing a "outright-bought" hardwaresite. Just look at the major articles they have published the last year and U will see.
All IMHO oc.
photoguy99 - Tuesday, September 27, 2005 - link
Tom's Hardware articles seem to be trending toward less interesting and less quality over time.I still read it, but most of the time find I prefer the AnandTech version of similar subjects.
One thing that is terrible about Toms - why no direct link from articles to a discussion topic?
Not only does it make it easier to discuss, but I consider it a huge benefit the the AnandTech authors read and participate in the discussion of the articles.
DerekWilson - Tuesday, September 27, 2005 - link
Is this not a discussion? :-)