F
or a long time, we’ve considered vid-
eocards that sport two GPUs second-
class citizens. They have all the
problems of multi-card solutions—namely
application incompatibilities and no multi-
monitor support—but fail to perform as
well as dual-card solutions, since multi-
GPU cards usually use slower midrange
GPUs. That’s finally changed with the new
RV770-powered Radeon 4870 X2, which
mounts two of ATI’s fastest GPUs on a
single card, without sacrificing power-
user features like multi-mon support.
The 4870 X2 is essentially two Radeon
4870 HD cards running in CrossFire mode
packed onto a single board: The X2 has
the same GPUs, the same 800 shader cores
running at the same 750MHz core clock,
and the same GDDR5 memory running
at 900MHz. But, there is one difference.
The single-GPU 4870 includes 512MB ofmemory, while the X2 has a whopping
2GB. However, the memory is duplicated
between the two GPUs, so the effective
frame buffer for the card is just 1GB. The
X2 also features a high-speed PCI Express
interconnect between the two GPUs,
which should, theoretically, boost the
efficiency of the shared GPUs. However,
in our tests, we didn’t see an appreciable
performance difference between a tradi-
tional CrossFire solution and the X2.
The 4870 X2 outperformed the previ-
ous single-card performance champ
in most of our benchmarks, delivering
playable frame rates at 1920x1200 and
2560x1600 in nearly every game we test-
ed. Naturally, the exception remains Cry-
sis, which, at its highest quality
settings, punishes nearly every
system we’ve tested. We’re
slightly concerned about the
accuracy of our Crysis bench-
marks; the ATI card seemed
to render far-off textures at
a higher resolution than the
Nvidia card. We’ll test further
and report back next month.
As always with high-end
cards, if you’re running a low-resolution display—pretty much anything
below 1920x1200—you won’t be able to
harness the full power of this card. At
lower resolutions, the 4870 X2 performs
exactly the same as the single-GPU 4870.
For anyone running a high-res panel, the
X2 truly kicks ass.
This card is a significant upgrade if
your GPU doesn’t support DirectX 10—and
is much better than some last-gen cards
that do. If you’ve been waiting to make
the jump to DX10, now’s the time to shell
out the bucks—you won’t see a better per-
former for quite a while. – W I L L S M I T HSapphire Radeon
4870 X2
The fastest videocard we’ve
ever tested—for the
most part
http://www.maximumpc.com | DEC 08 | MAXIMUMPC | 85
VERDICT$600, http://www.sapphiretech.com9
CrossFire per-
formance from a
single card. Can drive
1920x1200 gaming!Higher power require-
ments than a single-
GPU card; noisy.X-MENSAPPHIRE RADEON 4870 X2X-FACTORBest scores are bolded. Benchmarks are run on an Intel Core 2 Quad Q9770 Extreme, with 4GB of memory running Windows Vista. All tests are run at 1920x1200, with 4x AA
and 8x anisotropic filtering, unless otherwise noted.
BENCHMARKS
Radeon 4870X2 GeForce GTX 280
Crysis 4X AA/Very High (fps) 16.3 17.4
Crysis noAA/Very High (fps) 21.6 20.8
Call of Duty (fps) 81.8 68.3
Vantage Game 1 (fps) 10.8 17.6
Vantage Game 2 (fps) 13.0 12.1
UT3 (fps) 131.0 124
Grid (fps) 35.9 46.0Sapphire’s Radeon 4870 X2
sports 2GB of memory and
cranks the benchmarks
like we’ve never seen.