AMD Radeon HD 7990 graphics card

Top-of-the-line graphics cards usually come out first in a company’s annual launch cycle — they’re the fastest, the biggest and the most powerful.

AMD’s Radeon 7990 is out a full year after the first of the company’s 7000-series graphics cards — so it’s a little late to the party — but there’s no doubting its performance specs. It’s got two high-end GPUs on one board, with 6GB of RAM to keep things running smoothly.

AMD Radeon HD 7990: Design, features and setup

The Radeon 7990 is cast from the same mould as AMD’s previous reference graphics cards from previous years — a black plastic shroud covers the entire card, there’s hints of red, and three big fans arranged over a network of heat-pipes and cooling fins.

The rear of the card is covered with a metal plate that dissipates a little heat while protecting important circuitry.

Unlike AMD’s previous high-end designs, the 7990 dumps a lot of heat from its graphics chips directly into your computer’s case, rather than using a blower fan setup to expel it from the rear. The 7990’s approach relies more heavily on your computer’s case fans for cooling — sensibly, since your case’s fans will almost certainly be larger and in a better position to do so.

This also keeps the 7990 relatively quiet, even when it’s under full load during benchmarking, stress-testing or high-res 3D gaming.

The 7990 is a PCI-E 3.0 16x card, naturally, making full use of your gaming motherboard’s most capacious expansion slot. It requires two 8-pin auxiliary power connectors from your power supply, though, and AMD recommends a minimum of 750 Watts, keeping the 7990 squarely in the hands of enthusiast builds only.

The 7990 is made for multi-monitor use. It’s got enough graphical grunt to make multi-monitor 1080P gaming at high quality possible, and the ports to make this easy — one dual-link DVI-I, and four mini-Displayport connectors.

If you’ve got a monitor that uses HDMI, a miniDP-HDMI cable is a necessary investment, albeit one that only costs a few dollars on eBay.

It’s worth mentioning the sheer size of the 7990. It’s a full 30cm long, and we actually had trouble installing it into our test-bed — the motherboard’s edge-mounted SATA ports didn’t let the 7990 seat properly without a lot of cursing and pushing and begging.

If you’ve got a board with any obstructions along the entire length of the PCI-Express slot, try before you buy.

AMD Radeon HD 7990: Performance and specifications

The Radeon 7990 uses two Radeon HD 7970 GPUs, speed-binned to ensure only the best of the best are used. GPU speed is pegged at 1000MHz, slightly higher than standard 7970 clocks. RAM is clocked at 6000MHz (1500MHz with a GDDR5 effective rate of 6GHz).

Like the ASUS ARES II, it’s a serious piece of hardware. We ran through Battlefield 3, Crysis 2, Skyrim, and the 3DMark 11 benchmark to try and gauge its real-world and synthetic performance.

We tested the 7990 on an Intel Core i7-3770K system clocked at 4.3GHz, running off a ASUS Maximus V Extreme motherboard, a Crucial M4 256GB solid-state drive, 16GB of DDR3-2400 RAM and a Corsair AX-1200 1200W power supply.

This is the same system that we used to test the ASUS ARES II, which is a functionally similar card, as well as the Radeon 7790 and the NVidia GeForce GTX 680. We used AMD’s latest Catalyst 13.5 Beta 2 drivers for all our testing.

Crysis 2 ticked along brilliantly on the 7990, never dropping below the 70FPS mark on Ultra settings at 2650x1400 resolution. We played through the first level of Battlefield 3 at Ultra quality settings, achieving an average of 95FPS with no huge spikes either up or down. Skyrim’s difficult environmental calculations didn’t stress the 7990 — the 101FPS result is an excellent showing.

3DMark 11 shows the card’s outright benchmarking performance, with scores of X6810 and P17156. These results are great, and as a single-card solution the 7990 is top of the pack. If you’ve got the time and effort and money to invest in a high-end dual- or triple-card setup from NVidia, though, they’re beatable.

The Radeon 7990 is super-quiet when it’s idling — we found it quieter and less noticeable inside a closed case than the GTX 670 that it replaced. The fan design also means it’s relatively quiet even at full load, with an obviously-noticeable hum, but it’s a noise that’s far friendlier than the high-pitched scream of a flat-out blower fan.

It does have to dump a lot of heat into the case, but if you’ve got at least an exhaust and an intake fan in your case, this is easily dealt with with no noticeable adverse effects on our highly-strung, overclocked air-cooled CPU.

AMD Radeon HD 7990: Conclusion

The AMD Radeon HD 7990 is a serious card, and one that shows off the company’s ability to build a high-end dual-GPU setup that doesn’t have to be ear-splittingly loud under load. At the moment, and into the future, it remains an impressive feat that should keep even demanding gamers happy.