PCB Design, Specifications, Cooling System
We’ve got a reference sample of the Radeon HD 4830 card which is technically identical to the reference Radeon HD 4850 and has the same PCB. ATI’s development strategy proves to be profitable again. Thanks to the simple and inexpensive design with a 256-bit memory bus, the PCB could be used to release a new, less expensive, Radeon HD 4800, without making it too costly to manufacture.
The new card has the same power circuit as the senior model. It was not changed, being quite simple as it was, and the peak power draw of the Radeon HD 4830 is declared to be 110W like that of the Radeon DH 4850. We’ll check this out, of course. The GPU voltage regulator is based on a two-phase uPI Semiconductor uP6201 controller with four power transistors in each phase. Another chip from uPI, UP6101, is responsible for the memory chips. The PCB carries one 6-pin PCIe 1.0 power connector with a load capacity of 75W.
Like the senior model, the Radeon HD 4830 is equipped with Qimonda HYB18H512321BF-10 chips that have a capacity of 512Mb (16Mb x 32), a rated frequency of 1000 (2000) MHz and a voltage of 2.0V. The card’s memory frequency is 900 (1800) MHz, though. The memory bandwidth is 57.6GBps just like that of the GeForce 9800 GT. The overall amount of graphics memory is 512 megabytes. We guess such fast memory is going to be installed on cards that follow the reference PCB design. Nonstandard versions of Radeon HD 4830 developed by graphics card makers to reduce the manufacturing cost further will probably come with slower memory and lower overclocking potential. They will be less interesting for overclockers, of course.
The GPU is an ordinary RV770 chip that is no different from chips installed on the Radeon HD 4850. Without knowing how to decipher ATI’s marking, you can’t tell them apart. Two out of the chip’s ten SIMD arrays are turned off along with the corresponding texture processors. Thus, the total amount of execution units is reduced from 800 to 640 in comparison with the Radeon HD 4850 and the amount of TMUs is reduced from 40 to 32. Anyway, the Radeon HD 4830 seems to have higher potential than the GeForce 9800 GT although the latter partially makes up for its fewer ALUs by clocking them at a higher frequency. The significantly reduced core frequency agrees with our supposition that the card may use those RV770 cores that were not certified for installation on the more advanced Radeons. The core frequency is only 575MHz as opposed to 625MHz of the Radeon HD 4850.
Like the Radeon HD 4850, the Radeon HD 4830 is equipped with two dual-link DVI-I ports and a universal 7-pin mini-DIN connector for analog video output. HDMI support is implemented via an adapter. The card also has two CrossFireX connectors for building a graphics subsystem out of four cards but we doubt anyone would want to join more than two Radeon HD 4830 in CrossFire mode.
The Radeon HD 4830 uses the same reference cooler as the Radeon HD 4850.
We described it in our theoretical review of the Radeon HD 4000 architecture. The key point of this cooler is that it has single-slot form-factor, yet this is also its main drawback. Small size means lower cooling performance. To keep the latter at an acceptable level, there is a flat heat pipe pressed into the base. It ensures uniform distribution of heat in the heatsink consisting of thin aluminum plates. Considering the cut-down configuration of the core that is also clocked at a reduced frequency, this cooler should do its job just fine, but the hot air will remain inside the system case. Therefore you shouldn’t install this card into a poorly ventilated system case. The cooler’s fastening is secure and unlikely to damage the GPU die.
Now we are going to proceed to the practical part of this review. We’ll first check out how good the above-described cooler is and if the cut-down RV770 consumes less power than the full-featured core.