The contenders
We took an in-depth look at AMD's Radeon HD 6850 graphics card on October 22 and concluded that it was a good buy for £150. Priced up against the potent GeForce GTX 460 1GB card from NVIDIA, the Radeon HD 6850 held its own in benchmarks and matched the GeForce's feature-set.With NVIDIA setting conservative frequencies for the vanilla GTX 460, the company's add-in card (AIC) partners have released a number of custom-designed cards with higher clocks: the excellent Gigabyte GTX 460 1GB SOC being very much a case in point.
AMD's partners have now begun releasing pre-overclocked, custom-cooled HD 6850s. We've got a three-way face-off between Sapphire, PowerColor and ASUS - all of whom interpret Radeon HD 6850 cooling differently.
Without further ado, let's detail the various offerings and compare them against the reference card in an easy-to-understand table.
| Video card | AMD HD 6850 reference | Sapphire HD 6850 TOXIC | PowerColor HD 6850 PCS+ | ASUS HD 6850 DirectCu |
|---|---|---|---|---|
| Core clock | 775MHz | 820MHz | 820MHz | 790MHz |
| Memory clock | 4,000MHz | 4,400MHz | 4,400MHz | 4,000MHz |
| Cooler | Reference Dual-slot |
Custom Dual-slot |
Custom Dual-slot |
Custom Dual slot |
| GPU voltage adjust | Yes | Yes | No | Yes |
| PCB length | 9in |
9.5in | 8.5in | 9.5in |
| Power connectors | 6-pin | 6-pin x2 | 6-pin | 6-pin |
| Card weight | 617g | 785g | 511g | 526g |
| Overclocking util | N/A | TRIXX | None | SmartDoctor |
| Outputs | DL-DVI SL-DVI Mini-DP x2 HDMI |
DL-DVI SL-DVI Mini-DP x2 HDMI |
DL-DVI SL-DVI DP HDMI |
DL-DVI SL-DVI DP HDMI |
| Warranty | N/A | Two years | Two years | Three years |
| Retail price | £150 | £165 | £160 | £147 |
Comparing the 6850s
The trio of partner-overclocked cards top out at a disappointing 820MHz core. We know that the HD 6850 GPU is partial to running way past the reference speed; our card managed 900MHz without flinching. The reason for the mediocre overclocks is down to AMD, which insists that any partner 'OC' card must be limited to 820MHz. This flies in the face of the huge increases we see on NVIDIA's GTX 460 GPUs.
Sapphire
Talking specifics, the Sapphire HD 6850 TOXIC also cranks up the memory frequency to 4,400MHz - up from the default 4,000MHz. Based on the 9.5in-long Radeon HD 6870 PCB and also complete with two 6-pin PCIe connectors and upgraded heatsink-and-fan-unit, it's designed to be pushed much higher.
The TOXIC matches AMD's reference HD 6850's outputs, bringing in a pair of mini-DP v1.2 ports alongside HDMI and both single- and dual-link DVI. In effect, it's a Radeon HD 6870 card with an HD 6850 GPU.
PowerColor
The HD 6850 PCS+, meanwhile, ships with Sapphire-matching frequencies - well, the limits mandated by AMD - but on a smaller-than-reference PCB. PowerColor eschews the second mini-DP port and, instead, integrates a full-size DisplayPort on the I/O section.
ASUS
Playing the frequency game safest of all is ASUS. Based around the firm's DirectCu heatsink and shipping on a Radeon HD 6870-esque 9.5in PCB, the card bridges the PowerColor and Sapphire designs. The outputs match the PCS+', the size is identical to Sapphire's, but ASUS betters them both with respect to price and length of warranty.
The specifications suggest that Sapphire is looking for performance hegemony while ASUS and PowerColor are opting for a mid-way solution that balances price and speed. Partners need to be careful with pre-overclocked HD 6850 pricing as the next model up, Radeon HD 6870, retails from £185, imposes a ceiling on all Barts Pro cards.
