Radeon HD5670 Detailed Features

The main attraction of ATI's new line of video cards is the brand new GPU with its 40nm transistors and an improved architecture. The chip in the 5670 is called "Redwood" and is essentially half of the "Juniper", or if you like, one quarter of the "Cypress", the high-end chip that was first introduced in the HD5800 series, in September, 2009.

The Redwood die is very small, as can be seen with this comparison to a well known dimensional standard. ATI still managed to cram over a 600 million transistors on there, and the small size is critical to the pricing strategy that ATI is pursuing with these new releases.

The base card uses 512MB of GDDR5 memory, on a 128-bit bus with a 4.0 Gbps memory interface. This combination offers a maximum memory bandwidth of up to 64 GB/sec. There will also be 1GB versions of the card available, at a slight price premium. Memory prices are going through the roof these days, so it's not surprising that ATI is offering a choice here. When they cut the Juniper GPU in half, they kept the memory bus at 128-bit, so don't expect memory to be a bottleneck on this card. There may not be much room for memory overclocking, via the Overdrive tool distributed by AMD, but with only half the shader processors running point, it's not a capability that likely to be missed.

The H5GQ1H24MFR-TOC DRAM chip from Hynix is in the same family as the GDDR5 memory used in the HD57xx and HD58xx series video cards. It's in the lower tier, and only rated for 4.0 Gbps, which is a downgrade from the HD57xx series, which used a 5.0 Gbps version. An overclock to the 1250-1300 MHz range is going to be tougher with these chips, even if you increase the memory voltage. To be fair to ATI, this card is NOT meant for tweakers, it's meant to be an easy plug-and-play unit for people currently stuck with low end OEM or IGP graphics. As such, they are fully justified in optimizing the memory performance/price ratio to offer the best value to the intended customer.

The power section provides 2-phase power to the GPU based on the uP6201 controller; a very simple arrangement compared to the 58xx series, and more like what was used on the HD5750. The combination of a very low power GPU and low power GDDR5 memory means that a smart power supply design isn't really warranted in this situation. Even with the simple power scheme, they have achieved an incredibly low power consumption of 14W at idle and 61W under stress.

The assembly quality on the PCB was not the best I've seen, but I had engineering samples to look at. Before we dive into the testing portion of the review, let's look at one of the most exciting new features available on every Radeon HD5xxx series product, Eyefinity.

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