Core Clock: 625MHz Memory Clock: 1,986MHz Memory: 2,048MB GDDR3 Warranty: Two years (parts and labour)
We had a brief look at Sapphire's ATI Radeon HD 4850 X2 in November when the card launched, but at the time there was no official driver support from AMD – the company simply provided us with a pre-release hotfix driver that wasn't available for download. This driver had some issues where performance dived through the floor and then we learned that official AMD support wasn't forthcoming until at least Catalyst 9.1.
With Sapphire eager to get ahead of the game though, it has recently released a version of the Catalyst 8.12 WHQL driver with a modified INF file that enables support for the 4850 X2. The driver is WHQL certified and available for download direct from the company's website – this isn't quite official support from AMD, but it's as close as we're going to get for now and it's therefore time to get down and dirty with Sapphire's rather interesting dual-GPU monster. Read on to find out how it gets on...
At the time of our initial preview of the card, a number of ATI board partners had come to us to say that they were planning to release their own Radeon HD 4850 X2s very soon – so far, none of those promises have rung true and Sapphire has maintained its exclusivity in the market. At the same time, the card's price has dropped a bit since November – it's now available for under £260, which is over 15 percent less than the original £300 asking price.
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The card has the same number of stream processors as the Radeon HD 4870 X2, which means there are two 'full' RV770 GPUs under the heatsink each with 160 five-way shader units (making a total of 1,600 stream processors over the two GPUs). The clock speeds are exactly the same as a single Radeon HD 4850 as well – the core is clocked at 625MHz, while the GDDR3 memory runs at 1,986MHz (effective).
Unlike the standard Radeon HD 4850, Sapphire has included 1GB of memory per GPU on this Radeon HD 4850 X2 instead of the 512MB on a standard 4850. There is another, cheaper version of the card with 1GB of GDDR3 (512MB per GPU) – that retails for about £240 to £250 though, so we'd definitely recommend spending that little bit more on the 2GB variant based on the comparisons we've done between single 512MB and 1GB Radeon HD 4850 (and 4870) cards so far.
There are a couple of 80mm fans attached to an aluminium shroud with Sapphire's branding emblazoned onto it. The two RV770 cores are cooled by large aluminium heatsinks with a copper insert above each GPU core, while a third heatsink sits atop the PCI-Express switch positioned between the two GPUs. In addition, there are another couple of heatsinks on the power circuitry (one on the front and one on the back) that makes sure the PWMs are kept cool. Normally, we'd be a little concerned about a relatively tall heatsink placed on the back of the card covering additional power circuitry, but because of the card's length, it shouldn't cause any problems.
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Sadly, the card cannot be classed as quiet – far from it, in fact – and we think that's partly down to the decision to use fairly a basic aluminium/copper hybrid heatsink design on the GPU cores. It would have been more efficient to use a heatpipe design, but sadly there doesn't look to be enough room for that. And there are some components that would get in the way of a single heatsink design covering all three chips.
Sapphire has chosen not to use the Radeon HD 4870 X2's reference design PCB – probably because of the different traces required from the GPU(s) to memory – and has instead opted for its own design. It is longer than the Radeon HD 4870 X2 reference design (283mm compared to 267mm), which means that it will not fit in every chassis out there – be sure to check that you have enough room for the card to fit in your case.
Unlike the 4870 X2, the 4850 X2's memory resides only on the top side of the card – they're cooled with simple L-shaped aluminium cooling plates secured with three push pins. Moreover, the power circuit is also quite different to the Radeon HD 4870 X2's as well – most of the components are located down near to the dual power connectors (one 8-pin and one 6-pin) and is a seven phase circuit covered mostly by the pair of aluminium heatsinks – one on the front and one on the back.
There are a few components nestled in between the GPUs though (which prevent the single heatsink design we just mentioned) and are comprised of a pair of phases with each including a single choke and three MOSFETs. These appear to control power to the PLX PCI-Express switch, but it's not 100 percent clear based on the traces visible on the surface of the PCB
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On the PCI bracket, Sapphire has done what Asus did with the Radeon HD 3870 X2 – it has implemented four dual-link DVI connectors that will certainly please multi-monitor lovers because you can not only run CrossFire, but also connect up to four high-resolution digital displays. The bracket is rounded off with an analogue TV-out connector – Sapphire has included composite and component adapters in the bundle.
And while we're talking about the bundle, Sapphire has included a pretty good selection of items in the box. In addition to the aforementioned cables, there is a DVI-to-HDMI dongle, a DVI-to-VGA connector, two supplementary power connectors, a CrossFire connector and a selection of software that includes Cyberlink PowerDVD, DVD Suite and 3DMark Vantage.
Warranty & Support
The Sapphire ATI Radeon HD 4850 X2 comes complete with a two-year warranty that includes cover for parts and labour. During the first year of the product’s life, your point of contact should be the retailer. However, if you’re having problems getting hold of the retailer (or the retailer goes out of business), you should contact Sapphire’s support team directly. During the second year of the warranty period, you should talk directly with Sapphire.