Features of the 3D1
The 3D1 from Gigabyte is one of the unique products to hit the shelves. Designed on a 6800 Ultra sized PCB, you definitely need to make sure you case has the space required to fit this card. One of the great features is the cooling design. With the limited heat generation of the 6600GT cores, a single slot cooling solution is able to take care of the heat dissipation, even though there are two cores on the card. To combat the extra heat of the second core an extra fan was added to the cooler.
With the heatsink removed you get a good look at the bare card itself. Both cores are in parallel with each other with the memory modules surrounding the core like the 6800's have their memory modules. Each core has 128MB of memory attached to it on a 128-bit bus. Gigabyte claims this brings the unit up to 256MB of memory and a 256-bit bus, however, this doesn't actually hold true. The SLI link doesn't allow the cores to communicate with each others frame buffer, so in retrospect each core is limited to 128MB of memory on the 128-bit bus - just as if you were using two cards.
The GPU cores used are two standard GeForce 6600GT cores clocked at 500MHz each. These cores are both connected to a PCI Express x8 bus link on the card connector (creating the x16 link that the video cards need to operate).
In order to keep the memory speed up and the amount of space required down, Samsung F-BGA memory chips surround the two cores. The cooler actually makes contact with these modules, unlike most 6600GT cards which don't bother to keep the RAM chips cool.
Normally you don't need to have a PCI-E power adapter even when you use two 6600GT's so what do we need to for the 3D1? When you use two graphics cards, each card gets it power from their own power line on the PCI-E slot. Each slot gets 70watts of power, which is more then what a 6600GT needs. When using the single PCI-E slot, you are essentially trying to run two cards on one power line, which is simply not possible. To this the 6 pin PCI-E power plug is included to keep the power up to the card.
For our overclocking tests we used the Coolbits registry crack in order to open the core and memory voltage control. Unfortunately we didn't manage to gain any overclocking out of the card. When we tried to push the sliders even 1MHz over spec and run the test settings, we would simply be given the "System failed the test". No BIOS updated were available to try out, so we can't report any overclocking success on the card.
The board also refused to overclock on us, we only managed to hit 10MHz over spec FSB adjustment. Lowering the HT link speed, raising all the major voltages and loosening all the RAM timings didn't help.
We'll provide updates later on when a new BIOS is available to us.
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