Cards based around ATi’s Radeon HD5850 core have been available for a little while so it’s perfect timing for Sapphire to add the HD5850 to its Toxic family of factory overclocked cards. And, as with all the family members, the card not only gets a tweak to the core and memory clocks but also a better cooler than the reference design.
Out of the box a standard 1GB HD 5850 has a core clock of 725MHz and 1GB of GDDR5 memory clocked at 1,000MHz (because of the way GDDR5 works, this becomes an effective speed of 4,000MHz) and, it has to be said, a pretty noisy cooler.
For the Toxic edition Sapphire has increased the core clock by 40MHz so it runs at 765MHz, while the memory clock gets a more impressive tweak up to 1,125MHz (4,500MHz effective). It doesn’t stop there: should you want to try to wrestle even faster clock speeds out of the card, the Hynix H5GQ1H24AFR T2C memory chips are rated to 1,250MHz (5GHz effective).
Sapphire has used its own design of PCB for the HD5850 Toxic, which is longer than the reference design by some 12mm, at 256mm. That increase in length may not sound much but by retaining the end-on position of the two 6-pin PCI power connectors, it may make installing the card in smaller cases a bit problematic.
The name of the game with any overclocking is to keep everything as cool as possible, and as with all Sapphire’s Toxic cards the HD5850 features a completely different design of cooler to the reference design; the company’s own vapour chamber cooler. Sapphire’s cooler covers the PCB and is dominated by the centrally mounted 90mm cooling fan which pushes air out of both the front and back of the card.
The fan sits at the centre of a large cooling fin arrangement that is fixed to a large aluminium plate which covers both the GPU and the memory chips. Heat is transferred from the base into the fins by three copper heatpipes. The whole thing works well and even when gaming at high resolutions the fan noise is hardly noticeable. Adding to the cooling efficiency and stability of the card are Sapphire’s own Black Diamond chokes which have built-in heatsinks, while the voltage regulators get their own aluminium heat sink.
Built around an air vent on the back plate of the card are the output connectors; two dual-link DVI ports, an HDMI port and a DisplayPort, which just about cover everything you’ll need.
The small but useful box bundle includes the driver CD and a copy of ArcSoft SimHD, two 4-pin to 6-pin PCI-E power cables, a VGA/DVI adaptor and finally a longer than standard Crossfire bridge, which is a good idea as many motherboards these days have a large gap between PCI-E slots and this longer bridge connector is ideal to use in those situations.
Performance-wise the tweaked clock speeds offer a nice boost over the standard card. We tested the Toxic version of the HD 5850 using a couple of the most popular games with all the in-game details set to the maximum available and with 4x Anti-aliasing added.
Using FarCry 2′s built-in benchmark at a 1,680 x 1,050 pixel resolution we got an average fps (frames per second) of 70.38, which blitzes the standard card’s 57.80fps. Increasing the resolution to 1,920 x 1,200 pixels we got 58.11fps (52.4fps HD5850). It was a similar story with Crysis Warhead, the Toxic giving an average fps score of 43.11 (1,680 x 1,050) and 37.5 (1,920 x 1,200) compared to the standard card’s 37.82 and 30.44, at 1,680 x 1,050 and 1,920 x 1,200 pixels respectively.