Looking at the card, there's nothing too out of the ordinary for the most part when it comes to the HD 6870. We've got that fan at the rear of the card which is designed to push air over the top of the GPU and straight out the front.
Power requirements on the HD 6870 is double that of the HD 6850, meaning we need two 6-Pin PCI-E connectors. There's no requirement for an 8-pin one. These connectors have also been moved to the top of the card. Closer to the front we've got a single CF connector allowing us to put two of these cards together, again something we'll be doing very soon.
Connectivity is a little different when compared to the HD 6850 we looked at from Sapphire. The reference setup opts for a Dual-Link and Single-Link DVI connector, HDMI 1.4 port and two mini 1.2 DisplayPorts. If you're interested in knowing a bit more about the connectivity, I would again mention that it's probably worth checking out our AMD Radeon HD 6850 and HD 6870 - What We Can Tell You article.
Comparing there HD 6850 and HD 6870, there's some subtle changes. At the same time, there are a lot of things that the two cards share. As far as similarities go, they're both on a 40nm processor with 1.7B transistors. At default both carry 1GB of GDDR5 memory on a 256-bit memory bus. ROPs on both cards are the same at 32 as well.
There's a fair few changes, though. What I'll do is list the HD 6870 numbers normally and the HD 6850 numbers in brackets.
The HD 6870 carries 1120 (960) Stream Processors, a stock clock of 900MHz (775MHz) on the core and 4200MHz QDR (4000MHz QDR) on the 1GB of GDDR5 memory and texture units come in at 56 (48). Most of this information can be seen in GPU-Z.