AMD's Radeon HD 6450: UVD3 Meets The HTPC

Meet The Radeon HD 6450

Both Turks and Caicos (6450) are cut from the same cloth as Barts, meaning they inherit many of the optimizations we first saw in Barts. A few of the changes in Barts were Barts-exclusive or meaningful only when compared to Cypress, such as the Redwood memory controller, but elsewhere Caicos is picking up these improvements, giving the 6450 a leg up over the 5450.

Coming from the 5450, we’re going to see four big changes for the 6450:

1. Better performance due to higher clockspeeds and more functional units
2. Improved tessellation engine
3. New display controllers
4. UVD3

Better performance is fairly straightforward, which we’ll see in our benchmarks. Meanwhile the improved tessellation engine probably won’t make a big difference, as 5450 and 6450 are both too slow to play most games with DX11/tessellation enabled. So the notable and useful changes for the 6450 are going to be in the display controller and UVD3.

With the new display controller comes a new set of output options for the 6450. The 6450 has gained both DisplayPort 1.2 and HDMI 1.4a compliance. The former is going to make it very easy to drive three digital displays from a 6450—cards almost universally come with a VGA port as the 3^rd display otherwise. The latter is going to make it possible to drive 120Hz TVs at 120Hz for 3D content, primarily for Blu-ray 3D given the limited rendering capabilities of the 6450.

Of course to display Blu-ray 3D you need to be able to decode the frame-packed streams, and this is where UVD3 comes in. With UVD3 the 6450 gains the ability to decode MVC (frame-packed H.264) streams, along with full MPEG-2 decoding and MPEG-4 ASP (DivX/XviD) decoding. MPEG-2 and MPEG-4 are primarily for the benefit of mobile and Brazos platforms for energy efficiency and performance reasons, but the 6450 can tap into it all the same.

Moving on to the product itself, the card AMD shipped to us for review is very similar to our 5570 sample from last year, featuring a 6.61” low-profile card with a single-slot active cooler. At 27W TDP, power consumption is higher than the 5450, but a passively cooled low-profile 6450 should still be quite practical.

Our sample card is equipped with four 4Gbps Samsung GDDR5 modules running in 16-bit mode, adding up to the 64-bit bus we see on the 6450. Display connectivity is the same as in past AMD low-profile reference cards, featuring a DL-DVI port and a full size DisplayPort on the card, while a VGA port is at the top of the bracket attached to the card via a ribbon cable. The 6450 can drive up to three displays, including three displays through DP1.2 and an MST hub. For HTPC purposes we’d expect to see some cards replace the DisplayPort with an HDMI port.

AMD is primarily marketing this as an upgrade for Intel Sandy Bridge users, extolling the fact that they have DX11 capabilities and better drivers/compatibility than Intel. DX11 likely won’t make a difference for the games the 6450 can play, but we’ve seen first-hand that Intel still misses out on compatibility now and then. Perhaps AMD’s bigger advantage is that in the desktop space virtually all Sandy Bridge systems using the iGPU are using the HD 2000 GPU with 6 EUs instead of the HD 3000 GPU with 12 EUs; so the 6450 is placed against a sub-5450 GPU rather than a 5450-level GPU. In the mobile space however HD 3000 is the most common configuration, which makes things closer for the mobility versions of the 6450.