Asus EAH4890 and EAH4890 TOP
As we have already said in our earlier Radeon HD 4890 Review, the first batch of graphics cards based on the new ATI graphics core will use the reference PCB layout and cooling system design, and only a little later the market will welcome a few uniquely designed solutions. These two Asus EAH4890 graphics cards that will be racing against the GeForce GTX 285 SLI tandem in our today’s test session belong to the first generation of graphics cards, so they are designed exactly the same as the recently discussed PowerColor HD4890 Plus graphics adapter – only the brand name logo stickers are different. As for the exterior differences between Asus EAH4890 and EAH4890 TOP, there are none at all.
It is almost impossible to tell Radeon HD 4890 from Radeon HD 4870 without removing the cooling system, but nevertheless, it uses a new PCB, because RV790 is not pin-compatible with RV770. The voltage regulator is designed as “5+2”, where 5 phases are responsible for powering the GPU and 2 phases – for powering the memory. There are two Volterra VT1165 PWM controllers providing software support for power management. This technology on Asus EAH4890 cards is called “Voltage Tweak”.
Radeon HD 4890 PCB design implies the use of one 6-pin and one 8-pin power connector. However, just like with GeForce GTX 285, both graphics cards are equipped with two 6-pin PCIe 1.0 power connectors capable of handling up to 75W of power. Our regular readers already know that despite our expectations, the new card consumed a little less power than Radeon HD 4870 in our previous test session. As a result, the connectors load does not exceed 50W each even by Radeon HD 4890 OC, so there is nothing to worry about here and no real need to put 8-pin PCI1 2.0 power connectors on the new Radeon solutions.
The cards are equipped with 8 1 Гбит GDDR5 chips (32Mx32) providing the total of 1024MB with 256-bit access. According to the official ATI specifications, the memory should work at 975 (3900) MHz. and it does work at this particular frequency by both cards. Taking into account that the equivalent frequency is 3900MHz, we get 124.8GB/s bandwidth, which is way lower than by GeForce GTX 285. However, practice shows that it is not enough to have high memory bandwidth: you should also be able to really take advantage of it. Theoretically, Nvidia solutions have a certain advantage here, especially in 2560x1600, however, only gaming benchmarks will really answer this question once and for all.
Asus EAH4890 TOP
The only difference in technical specifications between Asus EAH4890 and EAH4890 TOP is the GPU frequencies: in the former case the core works at 850MHz, while in the latter – at 900MHz. The core has maximum configuration in both cases and consists of 160 superscalar processors (5 ALU in each, 800 ALU total), 40 texturing units and 16 RBE. So, if we compare Radeon HD 4890 CrossFireX with GeForce GTX 285 SLI tandem, it will only win in the number of ALU (1600 vs. 480), but will yield in the number of TMU and RBE (160 vs. 80 and 64 vs. 32, respectively). However, things we have just said about the memory subsystem are absolutely true here, too. It doesn’t make sense to compare the number of functional units in contemporary GPUs without taking into consideration their architectural peculiarities. Besides, software optimizations have pretty significant effect on their performance in real life situations.
Both Asus EAH4890 models are equipped with two DVI-I connectors supporting dual-channel mode, a universal analogue video output and two CrossFireX connectors. Unlike the competitor technology that allows tying together three graphics cards maximum, CrossFireX can accommodate up to four cards in multi-GPU mode. Although we have to keep in mind that not every mainboard supporting CrossFireX will fit a configuration like that, especially, with the cards of double-height, like Radeon HD 4890.
As for sound-over-HDMI support, it is implemented in RV790 and doesn’t require a sound card connection. There is an additional sound device in the system marked as Digital Output Device (HDMI) in the Control Panel and all you need to do to activate it, is either to select this sound device as a default sound card for Windows or to select it on the configuration options page of your video player. In the latter case only the soundtrack of your movie will be played through HDMI. Of course, you will need an appropriate adapter included with Asus EAH4890.
Just like the above described EVGA and Zotac, both Asus EAH4890 models use a reference cooler. ATI and Nvidia reference coolers are very similar from the ideological standpoint, because they use an aluminum heatsink cooled with a radial turbine and oust hot air outside the system case.
Overall, ATI’s cooler design is a little less effective, because it uses a heatsink with smaller effective cooling surface and a noisier fan, which crackling has become a distinguishing feature of Radeon HD graphics cards. However, it also has an advantage: it removes the heat from the power components of the voltage regulator circuitry via a special lug in the heatsink base and a greenish fibrous thermal pad. The memory chips transfer their heat to multi-layer elastic pads, and the GPU heat-spreader contacts the heatsink base through a layer of traditional dark-gray thermal interface that is used in most contemporary graphics solution coolers. Despite our concerns, this cooler performed pretty well in terms of cooling efficiency as well as acoustics, at least if you do not manually set the fan rotation speed to the maximum.