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PCB Design and Specifications

The first member of our asymmetric CrossFireX tandem is a copy of the reference card. While this is normal for top-end solutions like Radeon HD 5870 or GeForce GTX 285, inexpensive cards are often custom-designed. Anyway, this product only differs from the reference Radeon HD 5770 with the sticker on the cooler’s casing.


Asus EAH5770 (left) and ATI Radeon HD 5770 reference (right)

A few jumpers and smaller elements that we saw on an engineering sample of Radeon HD 5770 are missing. They must have been utilized by AMD for testing and certifying their new design and are not necessary on a serially produced product. We could find no other difference between the ASUS EAH5770 and the reference card, so you can refer to our review of the latter for details.

To remind you, the reference Radeon HD 5770 has a rather advanced “3+3” power system which is redundant for a 40nm RV830 chip but will allow reusing this PCB for the more voracious successors to the Juniper GPU. There is only one external power connector. With the introduction of the 40nm tech process, even the Radeon HD 5870 can do with two 6-pin PCIe 1.0 connectors whereas 8-pin PCIe 2.0 connectors are only installed on topmost dual-processor solutions like ATI Radeon HD 5970 or Nvidia GeForce GTX 295.

The GPU voltage regulator is based on an L6788A controller from STMicroelectronics. We thought that the memory chips were serviced by the pair of uP7701 chips but they are actually powered by the tiny VT242WF chips from Volterra. Technical documentation on this manufacturer’s products is hard to find in public domain, but we guess that a VT242WF combines three components necessary for a switching regulator: a controller, a driver and a power section. This is indicated by the active cooling of these tiny chips.

The EAH5770/2DIS/1GD5 has the same specs as the reference sample. It has a memory frequency of 1200 (4800) MHz. Coupled with the 128-bit bus, this provides a peak memory bandwidth of 76.8GBps. The total amount of memory is 1 gigabyte, which is a standard amount even for such inexpensive solutions as the Radeon HD 5700 series. The GPU is clocked at 850MHz and works in its full configuration with 800 ALUs, 40 TMUs and 16 RBEs. By the way, ATI’s previous-generation single-processor flagship Radeon HD 4890 has the same specs and only surpasses the Radeon HD 5770 in terms of memory bandwidth.

The graphics card has two DVI-I connectors and one DisplayPort. Coupled with the Eyefinity video controller implemented in all fifth-generation Radeons, it means you can connect up to three monitors simultaneously (one monitor has to support DisplayPort or you can use a DisplayPort à DVI-D adapter). There are also CrossFireX connectors on the PCB – we are going to need them today.

The reference Radeon HD 5770’s cooling system is a simplified and light version of the cooler installed on top-performance Radeon and GeForce series cards: a blower is cooling a heatsink connected with heat pipes to a base that contacts with the GPU die. The hot air is exhausted out of the system case through slits in the graphics card’s mounting bracket. The memory chips on the front side of the PCB are cooled while the chips on the reverse side of the PCB are not. This is not a problem as they do not get very hot at work.

The cooler is overall effective and quiet although many graphics card makers come up with more original solutions with the main purpose of singling their product out among identical copies of reference cards. Sometimes original coolers do ensure lower temperatures and noise and facilitate overclocking. The second graphics card is an example of that.

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