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Will it Crossfire? R9 280X & HD 7970 Scaling Tested


HardwareCanuck Review Editor
Staff member
Feb 26, 2007
By now everyone knows that AMD’s new R9 280X uses a repurposed Tahiti XT core which has been overclocked, putting its performance numbers somewhere between a HD 7970 3GB and a HD 7970 GHz Edition. During our time with the card, we were wondering: would the architecture commonality between the R9 280X and its HD 7970 predecessors lead to Crossfire compatibility? With the launch date quickly approaching, we didn’t have time to find out but now, with a bit of breathing room until AMD’s next products roll out, it is time to find out.

At this point you might be wondering: why even bother doing this when HD 7970 cards are available for extremely competitive prices? Well, if AMD is to be believed and the sales of HD 7970 and its GHz Edition counterpart continue apace, they will soon be gone from the retail channels. According to some of our retail contacts, that day is actually right around the corner with their stocks expected to be depleted by mid-November at the latest. At that point, anyone who wants to give their HD 7970 3GB an infusion of performance via Crossfire will either have to look towards used cards or hope for another solution.


It turns out that another solution may be to buy an R9 280X. Whether or not you’re a fan of AMD’s repositioning strategy is immaterial next to the phenomenal value its $299 price brings to the table, even without a Never Settle game bundle. With that in mind, we set out to test the theory that identical AMD ASICs will function together regardless of a card’s physical “name” or how the driver detects them.


So did our little experiment work? You bet. Without any issues whatsoever. The Catalyst software suite picked up both cards (in this case an R9 280X and HD 7970 GHz Edition), detected a Crossfire compatible system and we were off to the races. The only small hiccup was a slight reduction in the GHz Edition’s core speed to compensate for the lower-clocked R9 280X. Overclocking would have solved this discrepancy in an instant.

Below, we’ve included some scaling percentage comparisons between the HD 7970 GHz Edition / R9 280X hybrid setup and a standard HD 7970 GHz Edition Crossfire setup. Remember, a standard HD 7970 3GB would work here as well.


Not only do these results point to excellent Crossfire scaling across a large number of games (minus Assassin’s Creed for which profiles still don’t exist) but they also represent hope for HD 7970 users who many not have the cash to buy another card right now. This isn’t an error on AMD’s part either that will be patched in the future; the multi-generational compatibility was fully intentional and will continue into the future. That’s great news for Radeon users.

We should also mention that “mixed” Crossfire compatibility between HD 7000-series parts and their updated R-series siblings spans AMD’s lineup. For example, the R9 270X can be paired up with an HD 7870 GHz and the R7 260X works happily alongside an HD 7790. Clock speeds will be tied at the hip in every instance with the slowest card dictating final frequencies but as we mentioned before, overclocking will mitigate any performance shortfall.

AMD could have easily locked out this compatibility in an effort to boost sales of their new cards. They didn't do that. Instead, they erred on the side of providing the best possible experience for their current and future customers. It also gives them a leg up on the NVIDIA competition since GeForce cards have never supported so-called “mixed” SLI even if two cards use the same core design. For example, a GTX 770 –which is essentially a rebranded and overclocked GTX 680- can’t be placed in SLI alongside its predecessor. In some ways at least, this makes Crossfire more versatile than SLI.

While inter-generational compatibility may not be utilized by the lion’s share of gamers, AMD should be applauded for allowing their current users to retain a clear upgrade path without discarding one of their most expensive components.
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