GeXcube Radeon 9800XT Review
Overclocking and heat emission
Once I received the video card, I ran a series of overclocking experiments. As a result, we get the following maximum frequencies: the chip clock speed = 429 MHz, memory frequency = 391(782) MHz.
Further increase of frequencies resulted in the uprise of artifacts. The board heated up immensely, which tells to the need to modify the cooling system and proceed with the cooling. And there is definitely enough space to proceed: albeit with slight artifacts, the board kept on running at speeds up to 450-460 MHz (for the chip) and 400(800) MHz (for the memory frequency).
The video card was overclocked with the super popular Riva Tuner software which can hardly leave the Release Candidate stage (which is no surprise though, considering the flaws in the user interface :).
It is worth noting that the overclocking results is a purely subjective thing, and for each specific card the maximum frequencies may be varied. Anyway, the scatter of readings is rarely too large. This holds true not only for video cards of a single manufacturer, but for the vast majority of cards built on the same chip (in this case, it is ATI Radeon 9800XT).
It rarely happens when a manufacturer departs from the reference design requirements and either fits a faster memory or changes the operating voltage (as is known, the higher chip and memory voltages allow attaining higher operating frequencies). On the other hand, this allows the use not to worry much about the fate of the video card: a nominal cooler guarantees excellent cooling at both standard and increased frequencies.
By the way, let's look at the cooler.
Engineers at GeXCube decided not to rack their brains at developing their own cooler but inherited the design from the reference. In practice, the cooler proved to offer a very quiet operation.
Also note that the cooling system is very compact and does not block the adjoining PCI slot.
 To overclock to 400/450 MHz, we used additional fansThe cooler is made up of a copper base plate, a fan and a plastic lid which guides the air flow. Of special note is that the fan is positioned not right above the core, but with some displacement. This is done to eliminate the "dead spot" and maximize the efficiency of using the air flow.
The copper plate is positioned on the core and is fastened with four pins. The plate is also intended for cooling the memory chips. In respective points on the plate there are extruded pads which provide tight contact with the memory. Between the memory and the plate there is a layer of quite dubious thermal interface.
But they were overly generous with the thermal interface (a different type of paste :) for the 9800XT video chip.
Finally, the memory on the reverse side of the board is cooled by a copper plate where there is thermal interface of the third type :).
There was nothing to complain about this component: during the tests, the rear plate was heating immensely, which tells to a good heat transfer from the memory chips. By the way, the quality of assembly did appeal to me: the plate ideally fits to both the video chip and each of the memory chip. The same can be said about the rear plate. But the processing quality of the thermal interface of the front plate leaves much to be desired: on replacing the thermal paste with Zalman thermal paste, I was able to raise the operating frequencies of the chip from 429 to 440 MHz.
Note that the cooler fan is plugged in via a 3-pin connector. This implies the rotational speed can be adjusted. But it is inaccessible to the user - all is done automatically.
Reminding it once again that the card heats up immensely (even with the open test system). Therefore, for the summer period I would recommend fitting additional cooling, especially if the card is installed in a closed housing.
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