AMD Radeon HD 7790 Review Feat. Sapphire: The First Desktop Sea Islandsby Ryan Smith on March 22, 2013 12:01 AM EST
Bringing our review to a close, the launch of the Radeon HD 7790 is another precisely targeted launch by AMD. The 7790 is intended to fill AMD’s price and performance gaps between the 7770 and the 7850, and it does this very well, offering 84% of the 7850’s performance – or 130% of the 7770’s performance – for around $30 less than the 7850. In the world of sub-$200 video cards where every $10 matters, this is exactly what AMD needs to fill in their product lineup.
Meanwhile as the first GCN 1.1 GPU, Bonaire doesn’t greet us with any great surprises, and if not for the new PowerTune implementation it would be indistinguishable from Southern Islands (GCN 1.0). With that said AMD already had a strong architecture in GCN 1.0, so even minor changes such as PowerTune and a new GPU configuration serve to make a good architecture better. The new PowerTune will probably take enthusiasts a bit of time to get used to, but ultimately we’re happy to see AMD moving to using just full clock/voltage states and not relying on their clockspeed-only inferred states, as the former is going to offer more power savings. As for AMD’s functional unit layout for Bonaire – 14 CUs, 2 geometry pipelines, and 16 ROPs – it looks to have paid off handsomely for them. They’ve improved performance by quite a bit without having to add too many transistors or a larger memory bus, making it a great way to iterate on GCN midway between new process nodes.
The big question of course is whether 7790 is worth its $149 price tag, and factory overclocked models like the Sapphire worth the $159 price tag. From a pure price/performance perspective, right now things look pretty good for AMD and their partners. Against the rest of the 7000 series it has a very clear niche to fill, which is does so but without being so good as to make the 7850 redundant. Meanwhile against NVIDIA’s GeForce GTX 650 Ti things are still in AMD’s favor but it’s a bit murkier. A 12% performance advantage is distinct, but AMD’s also asking for nearly $20 more than most cheap GTX 650 Tis. At these prices there’s really no concept of a sweet spot since consumers often have fixed budgets, so instead we’ll point out that NVIDIA simply doesn’t have a suitable $150 video card right now; all they can offer are factory overclocked GTX 650 Ti cards.
Speaking of factory overclocked cards, our Sapphire HD 7790 Dual-X OC was exactly what we expected it to be. A 6-7% increase in clockspeeds leads to a 6% performance increase, showing that 7790 achieves the performance scaling necessary to make these cards viable. In this case overclocked cards are a very straightforward proposition: $10-$20 more for 6% more performance and typically a better cooler. This is all rather normal for factory overclocked cards, though we would point out that we have no reason to believe these overclocks aren’t achievable on stock-clocked cards.
Our one concern with the 7790 right now is one of memory size. Adding another 1GB of GDDR5 would definitely have a price impact, and having 2GB of GDDR5 on a 128bit bus would be a bit odd. But on the other hand we now know what the future of PC gaming holds: a lot of ports coming from a console with 8GB of GDDR5 memory. 1GB is going to look very small in a year’s time as those ports start arriving.
Ultimately we’re reminded of a discussion we had with the launch of the GTX 650 Ti last year, when we had the time to look at 2GB vs. 1GB on the 650 Ti and the 7850. Our conclusion at the time was such: “We have reached that point where if you’re going to be spending $150 or more that you shouldn’t be settling for a 1GB card; this is the time where 2GB cards are going to become the minimum for performance gaming video cards.” That conclusion has not changed. The 7790 looks good among the current crop of cards, but the 2GB 7850 is going to be so much more future-proof, at least in as much as a video card can be. At these prices consumer budgets are typically fixed and for good reason, but with 2GB 7850s available at around $180, it’s a very compelling upgrade for the extra $30. In 2013 it’s something worth considering if you want to keep a video card for at least a couple of years.