ATI Radeon X1650 XT
PCB Design and Cooling System
The Radeon X1650 XT printed-circuit board resembles the one of the Radeon X1600 XT, but this is just an appearance. It is a completely new design, largely determined by the peculiarities of the RV560. The two cards are the same size, but that’s in fact the single similarity between them.
You can spot significant differences even without removing the cooler. Note the placement and layout of the power circuit, for example. The bonding pad for a VIVO-supporting Rage Theater chip is placed at an angle of 45 degrees. The VIVO chip is not installed on our sample of the Radeon X1650 XT and we guess it will be missing on many other samples. Such functionality isn’t demanded nowadays, yet it raises the cost of the end-product.
As opposed to the Radeon X1600 XT that comes without an additional power connector, the Radeon X1650 XT can have one, but the connector is not installed on our sample of the card. Some power elements are not installed, either. There are only four power transistors of the voltage regulator on the PCB instead of eight. In the same place on the reverse side of the PCB a number of elements are missing, including a second controller, as it seems. This is indicative of rather low power consumption of the card. This also suggests that there may appear versions of the card with improved frequency or functional characteristics. On the other hand, the PCB might be developed to be future-proof and the empty seats in the power circuit may mean that this PCB is going to be used in ATI’s forthcoming mainstream products that will have more powerful graphics processors with much higher power consumption.
The RV560 chip is much larger than the RV530. Its die size is comparable to that of the RV570, but its packaging is smaller, without a protective frame. The Radeon X1650 XT’s cooler isn’t large or heavy, so the lack of the frame is not a problem if you handle the device properly. The main markings of the RV560 and RV570 differ by only one letter, G and D, respectively. So, this is indeed one and the same GPU in different packaging and with a different memory bus width. Our sample was manufactured on the 34th week of 2006 which corresponds to late August. Following the official specification, the GPU is clocked at 575MHz. There are fewer active subunits in the RV560 than in the RV570, so we can expect it to have somewhat lower heat dissipation and heat consumption.
Unlike the senior Radeon X1950 Pro, the Radeon X1650 XT is equipped with Infineon’s memory. There are four 512Mb 16Mx32 GDDR3 chips on board (HYB18H512321AF-14) for a total of 256MB accessed across a 128-bit bus. The rating frequency of the chips is 700 (1400) MHz, but they are actually clocked at 675 (1350) MHz on this card.
The Radeon X1650 XT has the same configuration of connectors as the Radeon X1950 Pro: two DVI-I and a universal S-Video/VIVO. There is a pair of new CrossFire connectors in the top left of the PCB – the two cards are joined with special flexible cables via these connectors.
The cooler installed on the Radeon X1650 XT should be familiar to you from our Radeon X1600 XT review. Its design is very simple: a copper base to which a folded metallic sheet is glued. The cooler has a small fan with straight blades that drives air through the ribbing and is covered with a black plastic casing. The fan uses a two-wire connection, it is not equipped with a tachometer as more advanced ATI Radeon models are. There are no advanced cooling technologies, like heat pipes or something, here.
This cooling system used to be criticized, and quite justly so, for being noisy. Perhaps the fan speed management works better on the Radeon X1650 XT – we’ll check this out in the next section. The cooler contacts the GPU die through a later of traditional dark-gray thermal grease. The memory chips are not cooled.