Even if the graphics card market is ruled by the PCI-Express version, some partners such as MSI still haven't given up on the aging AGP slot. The latest addition to the MSI's AGP series is the HD 2600 PRO in both 256MB and 512MB versions, both of which are passively cooled. MSI was kind enough to send us the 256MB version. The only difference between this card and the 512MB version is memory size; the cooler and the clocks are identical.
ATI's HD 2600 Pro GPU, or less commonly known as RV630, is made in the 65nm manufacturing process which is the main prerequisite for this card to be passively cooled, since it produces less heat and doesn't need a large heatsink like, for example, Sapphire's HD 3850 Ultimate. The core of the MSI HD 2600 Pro works at reference clock of 600MHz, and it is identical to the clock on the PCI-Express version. The memory, on the other hand, is a different story. We would really like to see GDDR3 memory on this card, but MSI has decided to go for the GDDR2 memory, probably to keep the price of this card as low as possible. The memory works at a lower clock of 400MHz (800MHz effective), and the card has a 128-bit memory interface.
As with he rest of the HD 2000 series, this card also supports DirectX 10, Shader Model 4.0 and comes with Dual-Link DVI with HDTV/HDCP support. The only noticeable difference between the AGP and PCI-Express versions is the lack of Crossfire connector and the small Rialto bridge chip placed on the back of the card. The Rialto bridge is used to transfer PCIe instructions to AGP, and without it, a PCIe GPU wouldn't work on the AGP port. Yet another difference is the 4-pin floppy connector which can't be found on the PCI-Express version. The reason for this is simple, the AGP port can't supply enough power to power this card.
As we mentioned in the beginning, MSI has decided to go for a passive cooling solution which uses dual heatpipes to transfer the heat away from the core to the heatsink located on the back of the card. When talking about passively cooled cards it's always worth mentioning that you should assure good airflow inside the chassis when using such cards, as passive cooling solutions are in most cases less efficient than their active counterparts. We were very skeptical concerning the performance of this cooling solution, but MSI has managed to pleasantly surprise us. The main credit goes to the large heatsink, as well as the fact that the RV630Pro core doesn't heat up too much, thus making it a perfect candidate for passive cooling.
As this card comes without the temperature sensor on its core, we measured it using the temperature probes placed on the GPU block and on the heatsink fins on the back of the card. It was interesting to see that the temperature on the GPU block is the same as the one on the heatsink fins, which means that the heat is effectively transferred from the GPU to the heatsink.
Bear in mind temperatures are measured in an open case environment, and in a closed case good airflow is a must. Of course, the main advantage of a passive cooling solution is it's completely silent, so if you are a "noise-freak" a passive solution is made for you. The 56°C under load is a great result for a passively cooled card.