After the initial installation the heatsink was immediately removed and the contact area was inspected. The new heatsink base clearly improves contact with the GPU core. It is interesting that there is always a bit less contact near one of the corners. We have seen this in all our previous reviews of other Arctic Cooling coolers. While some other coolers show better contact, the cooling performance of the ATI Silencer 5 is proof, that the contact is sufficient.
For the overclocking tests I used my ATITool overclocking utility version 0.25 Beta 1. ATITool has the unique ability to detect artifacts, or flaws, in a rendered image. As defined by ATITool, the maximum stable overclock on a card is the speed at which it is able to consistently (15 minutes in this test) produce no errors, or artifacts. ATITool detects ANY artifacts, even ones which will not be visible in game. Using the human eye to detect artifacts introduces subjectivity into the test, so despite the fact that an ATITool tested overclock will be characteristically lower than a human one, I will use this.
Temperature was measured with one case side open by reading the on-die thermal diode of our X800 Pro PCI-Express. Idle temperature was measured after letting Windows sit one hour at the desktop. Load temperature was measured after running 3DMark2001 looped for one hour. Both at the card's default clock of 507 / 520 Mhz.
We will be comparing the ATI Silencer 5 against this stock cooler of the X850 Pro. As you can see, the stock cooler has a copper base, is big and has memory cooling as well, so it will be hard for Arctic's coolers to compete against it.
Arctic Silver Lumière was used as thermal interface material for the GPU core in all installations. Lumière is a specially engineered testing compound - it needs no settle in time to reach its maximum performance, but it's not designed for permanent use. Arctic's Thermal Pad was removed using Arctic Silver ArctiClean (review here).
The fan was connected to the video card's fan output which features dynamic fan speeds - the fan speed is variated based on temperature. For all temperatures below 65°C it is 54%. The VGA Silencer does such a good job at keeping the card cool that it's always running at those 54%. I find this does not show the full potential of the VGA Silencer, so I also tested with fan speeds forced to 100%.
|Radeon X800 Pro PCIE||Maximum Core Clock||Sound level||Temperature Load||Temperature Idle|
|Stock cooler - dynamic fan||579 Mhz||48 dbA||61°C||38°C|
|Stock cooler - fan 100%||582 Mhz||62 dbA||57°C||38°C|
|ATI Silencer 5 dynamic||579 Mhz||39 dbA||56°C||35°C|
|ATI Silencer 5 100%||584 Mhz||52 dbA||53°C||35°C|
No matter what the actual fan speed is, the ATI Silencer 5 can keep your card cool. Even at the slow 54%, which the card supplies with the default settings, it's working really good. The 100% setting does not really increase overclocking potential much, I would say it is best to keep the fan running at whatever the video card sets it at.
The clicking noises which Revision 1 had are completely gone now, at any fan speed. Also the new fan seems to be even quieter than the fan of the first revision. Overall I must say that the fan is VERY quiet. Together with a high-end CPU cooler you can build a silent system which still is a power house.
When using an X800 with its smaller cooler, the differences will be much bigger. Here the ATI Silencer 5 can only give you a little better temperatures and a few extra MHz of overclocking, BUT it does that with a lot less noise as the sound level measurements show.