Board Analysis

Diamond Viper Radeon HD 2900 XT 1GB

Bottom of the card

Upper edge of the card

2.0GHz GDDR4 Memory

On paper, the 2.0GHz GDDR4 memory used on Diamond’s Viper Radeon HD 2900 XT 1GB is without equal in the desktop graphics market, nothing else really comes close to matching it for peak memory bandwidth. But as we discovered with the Radeon X1950 XTX, GDDR4 memory runs at much higher latencies than GDDR3, this hampers performance.

In the case of the X1950 XTX, the board’s GDDR4 memory ran over 200MHz faster than the X1900 XTX, yet in many benchmarks, the X1950 XTX was only 3-5% faster than the X1900 XTX. The delta separating Diamond’s Viper Radeon HD 2900 XT from the stock Radeon HD 2900 XT isn’t as large, so it’s possible that the performance between the two cards could be even slimmer in games that don’t take advantage of the Diamond board’s added memory.

Can you spot the difference between the 512MB card and the 1GB board?

Size comparison of the 8800 GTX and Viper 1GB

Reference board design

Physically Diamond uses the exact same reference board design for their Viper Radeon HD 2900 XT card. You’d be very hard-pressed to spot any differences between either card. Diamond merely slaps their sticker on the card’s fan, and ships the 1GB card out the door.

This means you’ve got the same dual-slot cooling found on the original Radeon HD 2900 XT 512MB. As we noted in our Radeon HD 2900 XT Performance Preview, this cooler runs considerably louder than NVIDIA’s GeForce 8800 cards under load during gaming, as well as its predecessor, the Radeon X1950 XTX. This is because the card’s fan spins at over 5,000 RPMs in these situations. Fortunately, the fan doesn’t kick up the RPMs until the GPU hits a certain temperature, so it’s possible to play some games without the fan kicking it into overdrive, but its all dependant on keeping the GPU below a certain temperature threshold. This is a task that’s difficult for the stock cooler to accomplish under the load of an intense 3D game.

Cooler up close

Diamond sticker on the fan

Moving to the front of the card you’ll see the card’s two dual-link DVI connections supporting HDCP. Diamond also includes an HDMI adapter, allowing you to pipe audio and video signals to an HDMI-equipped HDTV if you so desire. At the rear of the card lie the 6-pin and 8-pin PCIe power connections. If you recall, you must run power to the second 8-pin power connector, but fortunately it’s backward-compatible with today’s 6-pin PCIe cables.

An 8-pin PCIe power cable is only required if you wish to overclock the graphics card.

8 and 6-pin power

CrossFire connectors

Speaking of overclocking, we were able to push our Diamond cards to speeds of 856MHz core/1151MHz memory without any problems. At speeds higher than that, our copy of PowerStrip 3.76 beta would automatically restore the clocks back to 856/1151MHz. Apparently this is the limit of how far you can push the cards at this present time with this software.

Software bundle and accessories

Like other Radeon HD 2900 XT cards, Diamond ships the Viper Radeon HD 2900 XT with a voucher for the now cancelled HL2 Black Box bundle, which includes a copy of Half-Life 2: Episode Two, Team Fortress 2, and Portal. Also inside the card’s packaging you’ll find two DVI adapters and an HDMI adapter. Diamond also includes a component video cable, VIVO cable, and CrossFire cable inside the card’s packaging as well.

System Setup

Intel Core 2 Extreme X6800

EVGA nForce 680i SLI motherboard
ASUS P5W DH Deluxe

2GB Corsair TWIN2X2048-6400C4

ATI Radeon HD 2900 XT 512MB
Diamond Viper Radeon HD 2900 XT 1GB
8.38.9.1-rc2_48915.exe

NVIDIA GeForce 8800 GTS 640MB
NVIDIA GeForce 8800 GTX 768MB
ForceWare 162.18

300GB Western Digital Caviar SE

Windows Vista Ultimate

Benchmarks

Company of Heroes 1.7
F.E.A.R. 1.08
Elder Scrolls IV: Oblivion
Call of Juarez DX10 Performance Demo
Call of Duty 2 1.3
Half-Life 2 Lost Coast
Quake 4 1.3

Notes

In order to extract the most performance as possible from these cards under Windows Vista, we’re using the very latest beta drivers from both AMD and NVIDIA. The performance optimizations integrated into these beta drivers will eventually find their way into final drivers that will be posted online in the coming months (although 162.18 can be found today on nzone.com).