ATI Radeon HD 5970 Dual-GPU Video Card Review

Unlocked Overclocking

One thing that might shock many of our readers is that the ATI Radeon HD 5970 was better designed for overclocking. The PR department and engineers at ATI promised Legit Reviews that this card would be the best multi-GPU card we have ever seen from them when it came to overclocking and that they have added expensive components on the card to ensure great overclocking results for consumers.

Overclocking Ready Features:

• Digital Programmable Volterra Regulators
• 5.0Gbps GDDR5 Memory ICs
• Japanese Pure Ceramic SuperCapacitors
• Real Time Power Monitoring
• 400W Vapor Chamber HSF

All gamers and enthusiasts know that a bunch of neat features on a graphics card might sound good on paper, but cooling is still one of the most important areas that needs to be addressed. AMD is well aware of this and the cooler that AMD has included on the Radeon HD 5970 is a vapor chamber design that is rated to handle up to 400 watts! This means that the cooler has an additional 33% of cooling capacity that will be needed when overclocking. With solid looking components and a massive vapor chamber cooler on the card the only other thing that could be done to improve overclocking would be to speed bin the GPUs to get the best of the best for these cards. It appears that AMD has done that as well and have started to bin and sort the GPUs in order to find the low leakage ones to become the head of the Radeon HD 5970!

Anyone that has used the ATI Catalyst Control Center (CCC) overclocking utility called Overdrive will know the utility is usually rather limited and that you can’t adjust the core or memory voltages. Well, it appears that AMD has been a little more generous with the frequency ranges in OverDrive and has come up with a little utility called the ATI OverVolt Tool that can now be used to adjust the voltages of the graphics card. Legit Reviews was told that it would be up to each individual Add-In-Board (AIB) Partner to decide whether or not to include the utility with their retail cards. We got a chance to speak with Sapphire earlier this week and they confirmed that the utility will be included in one of their models.

Using the ATI OverVolt Tool is rather easy as you start out with the default card voltages of 1.05V on the core and 1.10V on the memory and then you can increase it to 1.1625V on the core and 1.15V on the memory. These are just modest increases, but AMD said that it is enough to greatly increase the overclocking possibilities of the Radeon HD 5970 graphics card.

AMD told us during a conference call that getting 850 MHz core clock and 1200 MHz memory clock should be what you can expect when overclocking these cards and for those that want to push even harder, higher clock speeds are possible.

With the stock voltages we were able to use auto-tune to reach 870 MHz core clock and 1155 MHz memory clock with 100% stability. This is a nice boost over the default clock speed of 725 MHz core clock and 1000 MHz memory clock.