Summary: With a beefier power subsystem, OC'ed clocks, and custom vapor chamber cooling, Sapphire's Toxic HD 4890 takes ATI's Radeon 4890 GPU to another level. In fact the card delivers performance rivaling the GTX 285 in some cases. But is it worth the price premium? Find out in today's review!
The GPU in question is ATI's recently released Radeon 4890. While it’s fundamentally based on the same architecture as the Radeon 4870 with 800 stream processors and 256-bit memory interface with GDDR5 memory, ATI has made a number of tweaks under the hood of the 4890’s RV790 GPU in order to enable higher clock speeds. Decoupling capacitors have been added in order to reduce signal noise at high clock speeds, while the GPU has been tweaked to consume slightly less power than its predecessor. Higher voltages also help the chip scale to higher frequencies, with ATI revamping the board’s power subsystem so it delivers more juice to the GPU. ATI also says they’ve retimed the entire chip to run at higher frequencies.
And enable high frequencies is exactly what they’ve done. The Radeon 4890 is clocked 100MHz higher than its predecessor – 850MHz. If you recall previous reviews of Radeon 4870 cards we’ve looked at over the last year, you’ll know that the 4870 generally topped out around 780-800MHz, and could really only go over that amount with specialty cards that offered the option of manual voltage adjustment. In comparison, the Radeon 4890 starts where only a select group of 4870 cards could be OC’ed to with a little bit of luck; and with a little bit of OC’ing, the 4890 scales much further from there – 1GHz is within reach with a quick slide of the mouse in Overdrive and some luck.
Or if you want something a little more certain, ATI’s board partners are brewing a crop of factory OC’ed 4890 cards that are fully backed by warranty. This has led to the clock speed war that we talked about.
Sapphire is one of the principal combatants in this war. Considering their history of providing some of the fastest tricked-out Radeon cards on the market though, that probably shouldn’t come as much of a surprise to most of you. Their Toxic line of video cards are known for their mixture of high clock speeds with superior cooling.
Sapphire’s got a new Toxic Edition card for the Radeon 4890 GPU, and as expected, Sapphire once again ups the ante by mixing factory OC’ed speeds with their exemplary vapor chamber cooling+heatpipes. Sounds intoxicating doesn’t it? The really sweet news is that’s not all Sapphire’s done with their latest Toxic board. Sapphire’s upped the card’s power subsystem as well. Let’s take a closer look shall we?
The most obvious difference between ATI’s Radeon 4890 reference design and Sapphire’s Toxic HD4890 is the Toxic board’s cooler. Both cards utilize heatpipe cooling, but Sapphire takes it to another level with their Toxic cooler.
At the heart of the Sapphire cooler is their vapor chamber cooling technology. We’ve written about this numerous times in the past, so we won’t rehash the detailed explanation of how the tech works here, but to make a long story short, vapor chamber cooling acts much like a heat pipe only it boasts lower thermal resistance than heat pipes, with higher heat conductivity as well. From the consumer’s point of view, Sapphire flattens their vapor chamber cooler into an ultra-thin chamber about the size of a conventional thermal plate. In fact, if you don’t look closely for the vapor chamber, you could easily confuse Sapphire’s cooling for a conventional heat plate.
Sapphire’s vapor chamber cooler is made completely from copper, which improves its ability to draw heat off the GPU thanks to copper’s superior thermal conductivity.
Sapphire doesn’t stop there though. To help the vapor chamber do its job Sapphire also adds three heat pipes to further aid in GPU cooling. The heat pipes are rather long, you can literally see them poking out of the right side of the cooler, and are made from aluminum. If you recall, ATI’s Radeon 4890 reference cooler features three heat pipes as well, but they aren’t this large (although they are copper).
Cooling the heat pipes is a dual-slot aluminum heatsink. This heatsink is outfitted with dozens of long fins, which helps to increase the surface area of the heatsink. Finally, at the base of the heatsink is a large thermal plate. Its primary responsibility is cooling the board’s memory modules, although it also helps to dissipate heat off the PCB.
An additional heatsink is also used to cool the board’s power circuitry. This is also found on the 4890 reference design, but the heatsink Sapphire employs has much larger fins than the stock ATI cooler (the heatsink on the ATI reference design is restricted in height due to the card’s blower-style fan).
Sapphire finishes the GPU cooling off with a fan that’s nearly 90mm in size: that’s bigger than many case fans! By using such a large fan, Sapphire can keep everything cool without having to crank up the fan’s RPMs to unbearably high noise levels. At idle, the fan ran in the 1640-1690 RPM range, and peaked to just 1850 RPMs while running looped Crysis timedemo runs. This allowed the Toxic card to run whisper quiet in operation.
Besides the beefed up cooling, the other hardware change Sapphire employs over the stock Radeon 4890 reference design is the use of an 8-pin power connector. Out back you’ll see that Sapphire employs one 6-pin PCIe power connector, and one 8-pin power connector. The 8-pin connector is capable of supplying the GPU with up to twice the power of a 6-pin connector, 150W versus 75W, so by integrating an 8-pin power connector instead of the second 6-pin connector, Sapphire is seriously upping the amount of juice that the card draws. In theory, this should improve your odds when OC’ing.
The 8-pin power connector is required in order for the board to operate; slapping a 6-pin PCIe connector in there isn’t enough. Thankfully Sapphire does include an 8-pin PCIe-to-Molex adapter.
In our testing with the card underclocked to run at Radeon 4890 speeds, the Toxic board consumed 21W more juice under load than the Radeon 4890 reference board under the same conditions: 314W for the Toxic vs the 4890’s 293W (idle consumption was within 1W).
The rest of the board’s design is the same as the stock Radeon 4890 reference board. Sapphire makes no changes to the board-level components, although they do utilize their trademark blue PCB rather than the red PCB ATI uses on their reference design.
Sapphire ups the clock speeds pretty significantly with their Toxic 4890. The graphics core is OC’ed 110MHz to 960MHz, an improvement of 11%. The board’s memory is also OC’ed, although not quite as dramatically, running at 1050MHz. This is 75MHz higher than the Radeon 4890’s 975MHz memory and equates to a 7% performance boost.
Sapphire ships the Toxic HD 4890 with a healthy bundle of software and accessories. Included inside the card’s packaging is a fresh copy of 3DMark Vantage, PowerDVD 7 (6-channel edition), and CyberLink’s DVD Suite, which includes a range of different CyberLink programs.
Intel Core i7-965
6GB OCZ Reaper HPC DDR3-1600
NVIDIA GeForce GTX 260 216 core
NVIDIA GeForce GTX 275
NVIDIA GeForce GTX 280
NVIDIA GeForce GTX 285
NVIDIA GeForce 8800 GT
ATI Radeon HD 4870 1GB
ATI Radeon HD 4890 1GB
Sapphire Radeon HD 4890 Toxic 1GB
300GB Western Digital Caviar SE
Windows Vista Ultimate 64-bit w/Service Pack 2
Call of Duty 4
Considering the hardware underneath, we were eager to see how far we could push our Toxic HD 4890 board. Fortunately, the card didn’t disappoint, clocking in at 1030MHz core/1170MHz memory. We actually were able to clock the memory at speeds over 1.2GHz, but artifacts would creep in occasionally. We had to clock the memory all the way down to 1170MHz to get the artifacts to go away.
Toxic clocks: As we’ve come to expect from Sapphire’s Toxic line of video cards, the Toxic HD 4890 ships with higher clocks than the reference Radeon 4890. The graphics core is OC’ed by 110MHz, running at 960MHz – just 40MHz shy of 1GHz we might add – while the memory is clocked at 1050MHz, 75MHz over stock.
No voltage adjustment: An increasing number of video cards are shipping with software utilities that support GPU/memory voltage adjustment. ASUS’ 4890 Voltage Tweak is the most common example among 4890 cards.
|© Copyright 2003 FS Media, Inc.|