X-bit labs

ATI RADEON X700 XT: Architecture Preview (page 3)

Category: Video

by Alexey Stepin , Tim Tscheblockov, Anton Shilov

[ 09/21/2004 | 04:54 AM ]

RADEON X700 XT: Taking a Closer Look

Alas, we couldn’t get a sample of the RADEON X700 XT into our greedy hands to put it under the most merciless tests in our own test labs. It was only a couple of weeks before the announcement, scheduled for September 21 then, that ATI Technologies finished the specifications of the RADEON X700. That was the reason why the company couldn’t make enough samples for the testing media around the world.

So, there are really very few RADEON X700 graphics cards in existence as yet, but ATI was very kind to offer X-bit labs to test the graphics card in their office, taking care about all the organizational issues. We couldn’t miss the opportunity and sent our reporter Anton Shilov – with our own testbed and all – to Munich, Germany, where the European office of ATI Technologies resides.

Anton got all its reports back to our lab in Tallinn, Estonia, to complete this review. The materials he gathered include the results of various tests as well as good snapshots of the RADEON X700 made on the spot. Thus we hope to provide you as much information as we do in any of our reviews we prepare in our labs. So, here it is, the hero of the day, the RADEON X700:

This is the elder model in the family, the RADEON X700 XT. The card is rather compact – the dimensions of its PCB roughly correspond to those of the GeForce 6600 GT, although the PCB itself looks more complex, due to the numerous small elements. You can notice a seat left for a Rage Theater chip, endowing the card with the VIVO functionality, but the chip was missing in our sample. The power circuitry is very simple – simpler and of fewer elements than in the GeForce 6600 GT. For example, there are only two big electrolytic capacitors here, while the power circuit of the GeForce 6600 GT has as many as eight.

The card offers the standard set of connectors, but a version with two DVI-I outputs is possible – this option may be demanded, considering the ever-rising popularity of LCD panels. By the way, it also means that the chip now has an additional TMDS transceiver that earlier GPUs from ATI had not. Like with the GeForce 6600 GT, we see a place left for an additional power connector here, although the card doesn’t actually need it. We will hardly see such a connector on off-the-shelf RADEON X700 XT cards, since they should be quite satisfied with the 75 watts of electricity the PCI Express bus can cater to it.

The new cooling system is a whole new story. It can’t boast any exotic features like a blower, but looks well-designed anyway: the copper heatsink under the casing should be efficient enough. The heatsink covers the GPU as well as the GDDR3 memory chips, which is rather a rare solution nowadays. You may remember that the GeForce 6600 GT and the RADEON X800 XT/PRO have no cooling of the memory chips at all.

As a matter of fact, GDDR3 memory chips generate less heat than GDDR2, for example, but they are anyway hot, working at frequencies of about 1 gigahertz. That’s why ATI’s design looks right, and it was only the tiny fan that raised our concerns. With a short diameter and small blades, it must rotate at a very high speed, which just can’t be well for the user’s audio comfort. We will discuss the noise factor below; now let’s view the other side of the card:

The back side of the PCB is very densely populated, too. Besides a crowd of small elements, there are empty places for four more memory chips (as said above, the RADEON X700 will come with 256MB of memory). As you see, the path from the GPU to the memory chips is not as straightforward as on the PCB of the GeForce 6600 GT.

The black metal bracket is an element of the cooling system and serves to hold the heatsink and prevent the PCB from any twists. Two screw-nuts are pressed into it. The spring screws go into these nuts and hold the heatsink. There’s nothing interesting left on this side of the PCB, save for the memory voltage regulators in the upper left corner and the sticker that says we deal with a sample of the RADEON X700 XT.

Unfortunately, we couldn’t make snapshots of the graphics core or memory chips – running this test session in almost “field conditions” we had no thermal paste and tools to remove the cooler to do that.

We have reasons to think, though, that the card carries 2ns K4J55323QF-GC20 chips from Samsung rated for 500 (1000DDR) MHz frequency. On the reference card, however, the memory was clocked at 525 (1050DDR) MHz, and the graphics processor at 475MHz.