ATI Radeon HD 4870 X2 previews show up

Monday 14th July 2008, 09:04:00 PM, written by Rys

Lucky media outlets web-wide have had some time to spend with R700 in Radeon HD 4870 X2 form recently.  While full analysis of the hardware is yet to break cover, the first looks from ATI's favoured media partners shows that it's pretty much what you'd expect from single-board Crossfire with RV770 at 750MHz, with 1GiB of GDDR5 for each GPU to use.

High-resolution testing at Tech Report shows that the configuration of RV770s on a single board, talking sometimes via a PLX PCI Express 2.0 switch and sometimes via a mysterious "Crossfire sideport", scales as well or better than two discrete HD 4870s do on a supporting mainboard.

Some of that is undoubtedly down to the memory available to each GPU, though, which makes the question of what the sideport is actually used for a deeper one.  Some well designed tests should be able to weed out what communication happens via that channel, though, if anything.

It's undoubtedly the fastest single graphics board ever produced, as long as your application or game supports it that is.  Raw headline figures of 2.4Tflops of FP32 compute show that there's some serious rendering muscle available should software be able to exploit the two GPUs and their available rendering modes.

Heat output and power consumption are both reasonable for the configuration, and the dual-slot cooler gets praise from some quarters for the job it does keeping everything cool.  It's a big ol' board though, and heavier than is probably safe to ship around attached to a system without something other than the PCI backplane to attach it to.

In short, AMD has the single-board graphics crown back with consumate ease, and while the execution is a little blunt, it'll stand toe-to-toe with GeForce GTX 280 on price, which is definitely in the X2's favour.

Check out Tech Report for more coverage, if their servers are able to take the Slashdot!

Discuss on the forums

Tagging

ati ± radeon, x2, rv770, crossfire, hd, 4870, afr


Latest Thread Comments (364 total)
Posted by Dooby on Saturday, 06-Sep-08 23:21:35 UTC
Still, without comparing different cards, and only difference OS's, thats a nice article for the next time someone whinges that Vista is slower for games.

Every test shows Vista equal or better than XP, on a £500 system too. Not bad at all.

Posted by pjbliverpool on Sunday, 07-Sep-08 11:50:55 UTC
8xMSAA scaling on the X2 is truly incredible! In Vista you only lose 15% performance on average from going to 0x to 8x MSAA! And thats including Crysis in the average which scales much worse than the other games. Most of those games showed virtually no performance disadvantage when going from 4x to 8x. :grin: And yeah, this article clearly shows Vista as the superior OS for gaming, especially if you have an X2.

Posted by ShaidarHaran on Sunday, 07-Sep-08 14:43:56 UTC
Quoting pjbliverpool
8xMSAA scaling on the X2 is truly incredible!

In Vista you only lose 15% performance on average from going to 0x to 8x MSAA! And thats including Crysis in the average which scales much worse than the other games. Most of those games showed virtually no performance disadvantage when going from 4x to 8x. :grin:
Freakin sweat.

Quoting pjbliverpool
And yeah, this article clearly shows Vista as the superior OS for gaming, especially if you have an X2.
LIES! dirty lies! it tries to takes our precious XP from usssss

Posted by ShaidarHaran on Sunday, 07-Sep-08 14:55:10 UTC
Look at that AA scaling! Jeez ATi... Why aren't they pushing this? Oh, that's right, because up until now, Vista has SUCKED! But it just got a whole lot better, if you're playing on an X2 at least ;)

Stalker fer cryin out loud! 52 fps in XP - 99 fps in Vista - grr, nevermind. CFX didn't work under XP. why even include the numbers then?

cripes! FREE 16x AA in Crysis of all games?

too bad the engine scales so poorly that the fastest dual-gpu video card of our times with some of the best AA performance known to man can't pull off even 30 fps @ VHQ 1920x1200

Posted by Dooby on Thursday, 11-Sep-08 16:13:53 UTC
Disabling CAT AI turns off CF on the X2 (ie, makes it a "single" 4870) and i get 49fps in CoD4.

Image: http://www.pogdesign.co.uk/stuff/cod4single.jpg

Enabling it, turns on the CF and i get 129fps

Image: http://www.pogdesign.co.uk/stuff/cod4dual.jpg

137% increase, from 100% more gpus. Niiiiiice.

Settings are 2560x1600, eveything Max'd, 4xAA (in game) 16xAF.

Posted by AnarchX on Thursday, 11-Sep-08 16:36:00 UTC
Do not forget that AI is bundled with game and filter optimizations.
So you did not only disable CF.

Posted by Silent_Buddha on Friday, 12-Sep-08 04:49:14 UTC
And AI also fixes bugs in rendering with affected games which could potentially slow a game down drastically if AI is turned off.

Regards,
SB

Posted by Raqia on Tuesday, 30-Sep-08 00:41:43 UTC
Quick question and sorry if it's been asked before:

What accounts for the difference in performance between crossfire and the x2 cards?

Posted by Kaotik on Tuesday, 30-Sep-08 03:07:12 UTC
Quoting Raqia
Quick question and sorry if it's been asked before:

What accounts for the difference in performance between crossfire and the x2 cards?
The bridgechip on X2 and in 512MB vs 1GB (per chip) memory in most cases, I believe

Posted by Raqia on Tuesday, 30-Sep-08 03:13:46 UTC
Quoting Kaotik
The bridgechip on X2 and in 512MB vs 1GB (per chip) memory in most cases, I believe
How much more bandwidth does the bridge-chip provide than crossfire? Is it also better latency?


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