Radeon 5670 Speeds and feeds

ATI’s latest Radeon card draws on the same roots as ATI’s other Evergreen boards. Its architecture is merely a cut-down derivative in order to reduce costs. Essentially ATI takes the Juniper XT core found in the Radeon 5770 and chops it in half to produce the Radeon 5670: while Radeon 5770 sports 800 shaders, Radeon 5670 has 400. 5770 features 16 ROPs with 40 texture units, while Radeon 5670 gets by with 8 ROPs and 20 texture units.

Radeon Specifications Comparison
	Radeon 5670	Radeon 4670 512MB	Radeon 4770
Manufacturing Process	40-nm	55-nm	40-nm
# of Transistors	627 million	514 million	826 million
Core Clock Speed	775MHz	750MHz	750MHz
# of Stream Processors	400	320	640
Compute Performance	620 GFLOPS	480 GFLOPS	960 GFLOPS
Texture Units	20	32	32
Texture Fillrate	15.5 GTexels/sec	24 GTexels/sec	24 GTexels/sec
Pixel Fillrate	6.2 Gpixels/sec	6 GPixels/sec	12 GPixels/sec
Memory Interface/Type	128-bit GDDR5	128-bit GDDR3	128-bit GDDR5
Memory Clock Speed	1000MHz (4Gbps data rate)	1000MHz (2.0Gbps data rate)	800MHz (3.2Gbps data rate)
Memory Bandwidth	64GB/sec	32GB/sec	51.2GB/sec

As you can see in the block diagram above, the Radeon 5670 features 5 SIMD cores with two 64-bit memory controllers paired to GDDR5 memory. Capacities of 512MB and 1GB will be offered, with both SKUs shipping with 4Gbps memory. The 512MB SKU should be sold for around $99.99 and up, while we’re told prices on the 1GB SKU should start around $114.99 and go up from there.

The Radeon 5670 is built on the same 40-nm manufacturing process as TSMC, but with half the number of stream processors (400 vs 800), it’s obviously going to be down on the 4770 when it comes to shading performance. Fewer texture units also means the 5670 will be down in the texturing department as well.


One positive for ATI though is die size. The Radeon 5670’s die measures just 104 square millimeters. In comparison, 4770 measures 172 mm2 and 4670 is 146 square millimeters, so the 5670 is a much smaller chip that should be cheaper for ATI to produce than preceding cards. In addition, thanks to the use of faster GDDR5 memory modules, the 5670 boasts two times the memory bandwidth of its predecessor – that’s a pretty substantial leap from one generation to the next in this class. It also sports about 13GB/sec of added memory bandwidth over the 4770.

Power consumption is another highlight for the Radeon 5670. We’re told that the board idles at just 14W, while typical power consumption is 61W. This, along with the 5670’s A/V features, should make it ideal for HTPC use.

Radeon 5670 cards

We’re not going to spend a lot of time discussing the Radeon 5670 reference board design, as frankly it isn’t as important for the 5670 as it is for more powerful cards in the Evergreen family. This is because ATI is allowing their board partners to produce their own unique 5670 boards right out of the gates on launch day. Board partners were forced to stick with the reference design for their Radeon 5700 and Radeon 5800 series cards, and are just now beginning to sell their own custom boards based on those GPUs.

As a result, you’ll see a wide variety of Radeon 5670 cards hit the market beginning today. They’ll be offered with an array of different cooling options, display outputs, and even with or without hardware-based CrossFire.

If you look at the upper left edge of the Radeon 5670 reference board, you’ll notice that our reference designed card isn’t equipped with the two 12-bit CrossFire connectors normally found on other Radeon boards. Instead the board’s CrossFire support is software-based.

Unfortunately, this comes with a performance penalty for enthusiasts who may wish to pair up two Radeon 5670 cards together. For ATI’s board partners, this helps to reduce their manufacturing costs. We’re told that you’ll see a mixture of 5670 cards with and without hardware-based CrossFire.

The mockup reference board photos provided by ATI for this review highlight a reference design with one DVI, one DisplayPort, and one VGA output as well as dedicated CrossFire connectors.

The future

ATI has two more cards planned for the value segment of the graphics market, the Radeon HD 5500 series and Radeon HD 5450, which is based on their final Evergreen chip, “Cedar”. Thanks to last week’s Mobility Radeon announcement, we already know that Cedar will ship with 80 stream processors and will likely utilize a 64-bit memory interface, but we don’t know the final clocks or pricing. We do have a couple of shots of these boards that we can share with you though: