A Review of the ASUS Radeon HD 5850 Direct CU Edition

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Custom Radeons Approach

Traditionally, custom video cards have been a losing proposition for buyers. While some existed which could boost clock speeds by a fair margin, the prices attached to the overclocked custom video cards were large, and it often made more sense to just buy the stock version of the next fastest card available.

This old rule seems to have changed, however, with the new ATI Radeon cards. The why I am not sure about. There are more vendors selling ATI cards now than ever, so perhaps the cause is competition. It could also be that the higher prices of video cards are forcing vendors to find other ways to present themselves as a good value. In any case, there are some very attractive custom cards available today, one of which is the ATI Radeon 5850 Direct CU from ASUS. Does the Direct CU offer an improvement over the reference design, or is it simply an attractive paperweight?

The Basics

ASUS Radeon 5850 Direct CU Review

The ASUS Radeon 5850 Direct CU is not a normal Radeon 5850 in numerous ways. The most obvious is the cooler. The large, heat-pipe brandishing cooler of the ASUS Radeon 5850 Direct CU looks impressive, but thankfully is about the same size of the cooler which is on a reference Radeon 5850.

What isn’t the same, however, is the PCB of the card itself. A normal Radeon 5850 is about 9.5 inches long, but the Radeon 5850 Direct CU measures about 10.5 inches long. In addition, this Direct CU card requires an eight pin and a six pin connect, while a normal Radeon 5850 only requires two six pin connections. These are significant differences from the normal Radeon 5850, so anyone thinking of buying this card should take note of them. A power supply and a case which will support a Radeon 5850 may not support the Direct CU version.

However, there is a reason for the extra juice. The Direct CU includes the ability to overvolt the video card. The ability to overvolt a video card is pretty rare, but seems to be coming into vogue with ATI’s new Radeons. Anyone who has ever overclocked a processor knows that the ability to overvolt is very important when attempting to achieve the highest speed possible.

Performance (5 out of 5)

For testing purposes, I compared the ATI Radeon 5850 Direct CU I had to the reference ATI Radeon 4870 which was previously in my system. The Operating System is Windows 7 64-bit.

Test System Specs:

  • Processor: Intel E8400 3.0Ghz
  • Motherboard: Biostar TP45E
  • Memory: 4GB DDR2-800
  • Main Hard Drive: OCZ Vertex Agility 60GB
  • Secondary Drive 1: Western Digital Caviar Blue 500GB
  • Secondary Drive 2: Hitachi 5200 RPM 500GB

To determine performance, I ran three benchmarks before installing the new 5850 and after. These were 3D Mark 06, Just Cause 2 Concrete Jungle, and Farcry 2 Ranch Short. In the case of Just Cause 2 and Farcry 2 Ranch Short I ran three loops of each.

3D Mark 06:

  • Radeon 4870: 12690 3D Marks
  • Radeon 5850 Direct CU: 14228 3D Marks

Just Cause 2 Concrete Jungle 1680x1050 All Details to Maximum

  • Radeon 4870: 25 Average FPS
  • Radeon 5850 Direct CU: 33 Average FPS

Farcry 2 Ranch Short 1680x1050 All Details to Maximum

  • Radeon 4870: 42 Average FPS
  • Radeon 5850: 49 Average FPS

As you can see, the Radeon 5850 provided a significant increase in performance. The largest subjective increase was in Just Cause 2. With the Radeon 4870 the benchmark was very choppy in a few areas. With the Radeon 5850 this was no longer noticeable. Also, my experience playing Just Cause 2 was increased because in the actual game was able to turn on higher resolution shadows and SSAO lighting. I had had these features turned off because the Radeon 4870 couldn’t provide a smooth experience with them turned on.

Cooling (4 out of 5)

ASUS Radeon 5850 Direct CU Review

Of course, the entire reason for purchasing a custom card like this is to overclock the snot out of it. The cooling solution therefor has to be very good. To test the cooling, I used Furmark to load the graphics card as much as possible. The fan was at default settings.

  • Radeon 5850 Direct CU Idle Temperature: 44 Degrees Celsius
  • Radeon 5850 Direct CU Maximum Load Temperature: 69 Degrees Celsius

The idle temperature of 44 degrees Celsius is not impressive, and is actually higher than what a normal Radeon 5850 would achieve. The load temperature is impressive, however. Normal Radeon 5850s usually have a load temperature of around 75 degrees Celsius.

Overclocking (5 out of 5)

To overclock the card I used the Smartdoctor tool which was shipped with the card as well as ATI Overdrive.

The card ships with stock speeds of 725 Mhz on the GPU and 1000 Mhz on the memory. Using stock voltage, I was able to achieve an overclock of 885 Mhz on the GPU and 1180 Mhz on the memory. This was extremely impressive, representing a 22% overclock on the GPU and a 18% overclock on the memory.

Having achieved that, I began to adjust the voltage settings. The highest overclock I could achieve was 950 Mhz on the GPU and 1220 Mhz on the memory at a voltage of 1.3V or above. This represents a 31% overclock on the GPU and a 22% overclock on the memory. To be honest, I was kind of stunned to find that this was possible. I have never been able to reach much beyond a 20% overclock on any video card I have previously owned.

This of course increased performance.

  • 3D Mark 06: Increase from 14228 3D Marks to 15990 3D Marks
  • Just Cause 2 Concrete Jungle: Increase from 33 Average FPS to 39 Average FPS
  • Farcry 2 Ranch Short: Increase from 49 Average FPS to 55 Average FPS

Increasing the voltage did have a major effect on the card’s temperature. The maximum temperature in Furmark at the highest settings reached 81 degrees Celsius, a 17% increase. The fan also became a little bit more noticeable as it was forced to work harder. However, the system remained 100% stable despite these temperatures.

Verdict (5 out of 5)

The ASUS Radeon 5850 Direct CU is a very, very impressive card. The overclock which could be achieved with it was stunning. It would be nice to have a Radeon 5870 to compare it to, because at these clock speeds the Radeon 5850 should be able to rival the Radeon 5870’s performance. If you’re not interested in overclocking, however, you’ll still enjoy the Direct CU’s cooler, which was very effective at keeping load temperatures down and was also quiet. The fan did not become distinctly audible until I ramped the overclock to the maximum.

And then we have the value proposition. The ASUS Radeon 5850 Direct CU is selling for $319.99 on Newegg and has been for some time. The least expensive Radeon 5850s sell for around $300. Is the Direct CU worth the extra $20 dollars? If you have a power supply and a case which can support this larger, more power hungry card, it absolutely is. I highly recommend the ASUS Radeon 5850 Direct CU. It is a well built card which provides excellent value for money.