ATI Radeon HD 5770/5750 Performance Preview

ATI Radeon 5770 reference board

The Radeon 5750 reference design

DirectX 11: Sooner than you think

We’re borrowing the phrase above from ATI, as it’s fittingly accurate at describing the shift from DirectX 10 to DirectX 11. Unlike previous DirectX introductions where the API itself and supporting hardware preceded the games themselves by months, if not years, the DirectX 11 switch is moving at lightspeed. In fact, while you may not know it, the transition to DirectX 11 is already well underway.

Microsoft quietly kicked things off first with the release of the August 2009 DirectX software development kit (SDK) a few months ago. This SDK includes DirectX 11 for Windows Vista and Windows 7 gamers.

By now you all know that a month after DirectX 11 was released, ATI introduced the world’s first DirectX 11 graphics card, the Radeon HD 5870. Boasting 1600 shaders and over 2 billion transistors, the Radeon 5870 is the fastest GPU you can buy today.

The very next day we saw the arrival of the world’s first DirectX 11 game, EA’s free to play RTS, BattleForge. BattleForge has actually been on the market since March of this year, in fact it was one of ATI’s launch titles for DirectX 10.1. The game was just patched to support DirectX 11, with BattleForge using the DX11 API to accelerate a form of screen space ambient occlusion (SSAO) known as high definition ambient occlusion. The texturing demands of enabling HDAO are pretty high, as you can imagine this can have a detrimental effect on your frame rate, even with the latest DX10 cards. To reduce the texture sampling burden, BattleForge uses DX11’s compute shader to store the depth and normal buffers on the chip’s local data store. With this tweak enabled, performance is improved nicely over DX10-based SSAO, and even delivers good improvements over ATI’s previous DX10.1 implementation. We’ve got benchmarks you’ll want to check out a little later in this article.

Besides BattleForge, in December we should see the arrival of the second DirectX 11 game, DiRT 2. Codemasters says DiRT 2 will leverage the tessellation unit to bring us dynamic water surfaces and cloth (basically flags that flap a little more in the wind, more water ripples, etc), as well as more animated crowds sitting in the stands near the race tracks. The developers are also using shader model 5.0 to enhance the game’s depth of field and shadow filtering, while the compute shader is used to optimize post-processing effects.

Moving into 2010, a trio of titles is tentatively scheduled for release in Q1 of 2010. GSC is working hard to bring STALKER: Call of Pripyat to market. We posted a few DX10.1 vs DX11 screenshots a few weeks ago. In the shots you can see Pripyat’s DX11 contact-hardened shadows, where shadow edges are sharp where they contact the object that's casting the shadow, and get blurrier further away from the object, while tessellation is used to add more detail to the character’s gas mask. These are subtle, but nice effects that mimic what you see in real life.


Also coming in Q1’2010 is Rebellion’s Aliens vs Predator. The DX11 version of the game will use the tessellation unit to provide more detailed characters and game environments, while the compute shader will also be used for HDAO. Also coming in Q1 is Turbine’s Lord of the Rings Online.

Overall ATI says 20 DirectX 11 titles are currently in development, with more on the way. For instance, DICE showed off an experimental version of their Frostbite 2 game engine that used the compute shader to speed up deferred shading, but we don’t know if it will ultimately be used or not in the PC port of Battlefield: Bad Company 2 when it ships next year.

Basically though, developers definitely seem to be jumping onboard with DX11 faster than previous DirectX introductions, and like DX10, DX11 will be used to enhance image quality (with DX11 features like tessellation), improve performance, or both.

ATI’s Radeon 5700 series: DirectX 11 for the masses

With next generation content right around the corner, gamers hoping to play these games in their full glory are going to need a DX11 graphics card. ATI’s Radeon 5870 will obviously give you the best experience, but not everyone can afford to shell out nearly $400 for a new graphics card.

Priced at $259, the Radeon 5850 delivers very good performance at a more affordable price point, but it’s still priced out of the reach of the casual gamer and mainstream audience.

This is where the Radeon 5700 series comes in. With pricing starting as low as $109 for the Radeon 5750 512MB, it’s a very feasible option for a lot of gamers on a budget. Based on the same DX11 architecture powering the Radeon 5800 lineup, the 5700 series of cards have been designed to give you all the key features found in ATI’s flagship DX11 products, only they’ve been tweaked to be cheaper to produce.

Do these tweaks cripple the card’s performance? And how well do the 5700 cards perform in comparison to ATI’s Radeon 4800 lineup? Those are some of the questions we plan to answer in today’s article. First let’s take a look at what changes ATI has integrated into the 5700’s architecture.