|MSI N460GTX Cyclone 1GD5/OC Video Card|
|Reviews - Featured Reviews: Video Cards|
|Written by Bruce Normann|
|Wednesday, 11 August 2010|
Page 5 of 19
MSI N460GTX Cyclone Detailed Features
With high-end video cards, the cooling system is an integral part of the performance envelope for the card. Make it run cooler, and you can make it run faster has been the byword for achieving gaming-class performance with all the latest and greatest GPUs. The MSI N460GTX Cyclone uses a fairly standard GPU cooler concept that is similar to the reference design, but it contains some enhancements, some more visible than others.
Two flattened, 6mm diameter heatpipes are clamped between the fairly thick, nickel plated copper mounting plate and a small aluminum heatsink, passing directly over the GPU die. Once they exit from there, they spread to the outer reaches of two semi-circular aluminum fin assemblies. Considering the power density of modern GPU devices, it makes sense to contact every square millimeter of the top surface with the heatsink if you can. The GF104 chip, like most NVIDIA GPU packages has a very large heat spreader mounted to it, and the copper mounting plate covers it with room to spare.
The air all flows out in a radial fashion from the centrally mounted fan, and very little makes it out the vents on the I/O bracket at the rear of the case. Make sure your chassis has plenty of airflow, in the right direction, in order to move the heat generated by this card up and out of the case. This cooler design does not seem all that well suited to multi-card SLI applications. Of course, that doesn't prevent it from doing just that, in a very convincing manner. Sometimes you just have to engineer your way around unusual design choices; the most famous case in point being the Porsche 911, another air-cooled design which succeeds brilliantly.
The GPU makes direct contact with a copper plate that is soldered to the heatpipes passing directly over the top of the GPU. The thermal interface material (TIM) was very evenly distributed by the factory, but was applied slightly thicker than necessary. One day, anxious manufacturing engineers are going to figure out that too little TIM is better than too much. For the rest of us who pay attention to these things, a thorough discussion of best practices for applying TIM is available here.
Here is a close-up of one of the Hi-c tantalum capacitors on the back side of the card. They are incredibly small for the amount of charge they hold, which allows them to be placed much closer to the active components they support. This greatly improves the filtering performance at high frequencies. If you remember when ATI upgraded the HD 4870 GPU to HD 4890 status, it was the addition of small filter caps right on the GPU package substrate that allowed the 4890 to reach such high clock rates. Tantalum caps were what made that design change possible.
The main power supply controller chip used on the MSI N460GTX Cyclone is an NCP5388 chip from ON Semiconductor. It is a 2/3/4 Phase PWM control IC that does not supports I2C software voltage control, however the NVIDIA BIOS provides its own software control that interfaces with the controller at the hardware level. The VRM section uses a relatively simple and straightforward 3-phase design for powering the GPU. I've seen some custom GTX 460 designs recently that bump this number up to at least four phases, but the three provided by the reference design seem to work well. A couple of small ANPEC APW71xx integrated controllers provide 1.5 volts to the GDDR5 RAM, and 12V to the board's control circuits.
The MSI N460GTX Cyclone uses standard Power-SO8 packaging for the Single N-Channel MOSFET power transistors and drivers in the VRM section. This discrete implementation gives up the opportunity to save a little space, but it does give the designer a broader choice in component selection, compared to a DrMOS design. The 4935N devices installed here can source a whopping 93A at an ambient temp of 25C, and are downgraded to 59A at 85C. We all know how hot video cards get, so it's good to have plenty of reserve current capacity for these power devices.
The memory choice for the MSI N460GTX Cyclone 1GD5/OC is consistent with the NVIDIA reference designs. The basic GTX 460 specs only require 900 MHz chips for the memory, but most cards have been using these Samsung K4G10325FE-HC05 GDDR5 parts, which are designed for up to 1000 MHz. The MSI Afterburner software supplied with this Cyclone edition doesn't have the capability to increase memory voltage, so don't presume that you will get much more than the rated memory speed. The 1250 MHz versions of this chip have been mediocre overclockers on the Radeon platform; we'll have to see if the lower specified parts are a little more willing to exceed their ratings.
Now that we've had a good tour of the MSI N460GTX Cyclone, inside and out, it's time to put it to the test. Well, Benchmark is our first name, so don't worry. There are a wide variety of tests waiting for you in the next several sections. Let's start off with a complete description of the Video Card Testing Methodology.