02 - A closer look

The MSI NX6600GT AGP runs at slower clock speeds than the PCI-Express cards. A typical PCI-E 6600GT runs at 500/500 for both core and memory, whereas the NX6600GT's memory speed is only 450MHz.

MSI has populated the card with a set of four Samsung K4J55323QF-GC20 Graphics DDR3 SDRAMs. This means the memory has the potential to work at least up to 500MHz and will probably overclock quite well.

Removing the two heatsinks, two chipsets and the 4 memory modules are exposed. If you compare the PCB to the 6600GT reference PCB for the PCI-Express version of the card, the first difference you will note is the slightly rotated design of the GPU and memory. This was done so that an extra chip could fit on the board, namely the High Speed Intraconnect (HSI), which is the smaller green chipset seen in the picture below.

The front side of the card (click to enlarge)

The HSI chipset is a bridge between the PCI-Express intended GPU and the AGP interface. Nvidia didn't bother to create a different architecture for the 6600GT chipset to work with AGP, but instead reused the much simpler and cheaper HSI bridge (HSI has been used before to enable AGP cards to operate with the PCI-E interface).

A view at the back side of the card (click to enlarge)

This means that the 6600GT AGP version is somehow running under compatibility mode which might cause a drop in performance compared to the PCI-E version.

A picture from a different angle.

Another difference making the 6600GT AGP stand out, is the requirement for a power connector to operate correctly. The PCI-E version does not need extra power as the architecture can provide up to 75V through the PCI-E slot.

The 6600GT chipset.

The D-Sub, DVI and VGA connectors.