Radeon HD 4870 X2: Four Cards Compared

Asus Radeon HD 4870 X2 Top (EAH4870X2 TOP/HTDI/2G/A)

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The TOP model is shipped with higher-than-reference clock frequencies. The standard for the GPU is 750 MHz and Asus increases this to 790 MHz. The graphics memory speed is only slightly increased, from the standard of 900 MHz to 915 MHz (DDR5 frequency 3660 MHz).

For this comparison, we don’t do additional overclocking because the overall gain turns out to be rather low. But if you want to take the card to its limits, you can get quite a bit more out of the TOP model. The test card can easily do a GPU frequency of 822 MHz, which is the best value in the test group. A nice addition is the extension of Overdrive . Asus increases the usual limit in the driver from 800 MHz to 900 MHz. This option functions independently of any particular software version, because it is available in the Catalyst 8.10 from AMD’s homepage.

The graphics memory has similar overclocking potential. The reference speed is 900 MHz and Asus sets the TOP model to 915 MHz. But our test card can easily do a stable 990 MHz—again the best value in the test group. As long as you install only Catalyst 8.10, the fan profile works without a problem, with the fan adjusting its speed according to the clock speed. With the additional overclocking, it spun at 3,400 RPM to maintain 85°C. When you use the preset Asus settings (790 and 915 MHz), the temperature can rise to 89 or 92 degrees, which is due to the lower fan speed of 3,000 RPM.

If you install the Catalyst 8.10 with the Asus Smart Doctor that comes included, the fan profiles get screwed up. In 2D mode the fan speed rises from 27% (standard) to 65%, and the noise level rises from a quiet 37.0 dB(A) to a loud 46.2 dB(A). These values sound alright, but you can see the issue when looking at the high temperatures in 3D mode. The fan doesn’t turn on reliably until the temperature reaches 96°C. It’s an inconsistent issue at best, though, as one of the five tests did see the fan turn on at a correct time.

Asus didn’t put in games or additional software. Instead, the company gives you two power adapters, and the 8-pin adapter is rather rare. You get HDMI through using the DVI adapter, and it comes with a bridge for Crossfire. Finally, you get a leather bag for CDs and DVDs as a special extra.

Naturally, despite all of our praise for this board’s overclocking headroom, bear in mind that Asus is only going to cover your card with a warranty if it wasn’t fried in the line of duty. Overclocking can be risky, especially at the temperatures we’re talking about here. You pay for Asus’ additional clock speed, plus the luxury of factory coverage. Taking the card past that point is at your own risk.

Asus Radeon HD 4870 X2 Top

As a TOP model, the card comes overclocked, but it can take significantly more tweaking before showing instability—it has the largest overclocking potential in the test group with a maximum of 822 MHz (GPU) and 990 MHz (memory). As long as you run the card with only Catalyst 8.10, the fan profiles work well; problems occur only when you install the Asus Smart Doctor.

• Advantages
• Disadvantages

• Best overclocking potentialOutstanding fan profiles with Catalyst 8.10Adapter for 8 pin power supply
• Smart Doctor + Catalyst 8.10 causes errors