AMD 780G Chipset and Athlon X2 4850e Preview
Introductions and Specifications
We generally don’t use integrated graphics. You might not use integrated graphics. But there are more motherboards with integrated graphics sold than discrete cards, according to data published last year by Jon Peddie Research. That means you probably have friends and family buying systems with built-in graphics engines.
Guess what happens when the work day is done and you take them into battle with you through a little Enemy Territory or Company of Heroes? Poor performance likely gets them killed over and over. Talk about a real bummer. We're WoW junkies ourselves, and you can’t imagine how many of the guys blame raid wipes on the speed of their graphics cards.
Fortunately, even as the latest games transition to advanced DirectX 10 functionality, quickly outdating yesterday’s value GPUs, the hardware vendors manufacturing integrated graphics chipsets are revamping their offerings. Intel, for example, recently slipped out its G35 chipset with the GMA X3500 graphics core. Sporting DirectX 10 and OpenGL 2.0 support, along with hardware vertex shading, the GPU would seem to be a great play on mainstream gaming in Vista. Could the company have its first gamer-worthy integrated chipset?
Not if AMD has anything to say about it. The 780G platform launching today combines the core logic expertise and graphics technology brought in from ATI with AMD’s latest low-power Athlon X2, yielding a very fast, very inexpensive platform that won’t rack up a substantial energy tab. Additionally, the chipset supports a new feature called Hybrid Graphics—a Vista-only capability that harnesses the power of an add-in card, combines it with the integrated engine, and gives you a CrossFire-like experience at a price point so low that AMD doesn’t want to call it CrossFire. Sounds like just the ticket for cost-conscious gamers eager to hang with the big boys. You can read more about Hybrid CrossFire in our initial look at the technology right here.
AMD 780G High-Level Overview
A motherboard built on the 780G chipset consists of two core logic components: the 780G northbridge and AMD’s new SB700 southbridge.
Despite its 205 million transistor composition, the 780G is actually a tiny little piece of work, thanks to a move to 55nm manufacturing. At idle, AMD says the northbridge sips less than a watt. Pretty impressive when you consider the cutting-edge functionality wrapped up in the silicon.
For instance, the chipset supports a HyperTransport 3.0 link to the new AM2+ socket interface. Past chipsets worked with HyperTransport 1.0 running at 1 GHz DDR. The 780G ups the link speed to 1.8 GHz, yielding nearly 15 GB/s of bandwidth. That throughput is particularly important to the 780G, since the built-in graphics processor has to talk through the processor’s memory controller in order to pull data from system RAM. Naturally, as you scale HyperTransport performance, 3D frame rates will go right along with it.
Of course, getting the benefit of HyperTransport 3.0 requires a processor that supports the interface. One of the new Phenom chips will do the trick. An older Athlon X2, such as the one we’ll be looking at in a bit, will not. Just to be clear, the new AM2+ socket is backwards compatible with CPUs designed for the AM2 interface—it just reverts back to HyperTransport 1.0 link speeds.
With plenty of data moving between the CPU and 780G, there’s room for lots of high-bandwidth connectivity. The northbridge boasts 26 PCI Express 2.0 lanes. Sixteen are reserved for a single discrete graphics slot, six can be set aside for x1 upgrade slots and onboard peripherals, and the last four interface with the SB700 southbridge. We talked to AMD about the possibility of a motherboard vendor splitting the 16-lane link into a pair of CrossFire-enabled connectors. However, the link is fused together, which makes sense given the chipset’s mainstream pedigree.