I added a second UAD-1 card to my PC, but it doesn’t work. Why not?

Most likely, it has to do with Windows 32-bit RAM limitations. if the system had 4 GB of total, allocated RAM, then enough will need to be removed form the system to make the UAD-1 card show up properly. Bear in mind that existing UAD-1 cards, video cards, and other DSP processing cards will infringe on installed RAM. Even if only 3 GB of DIMM’s are physcially installed, you still could exceed the 4 GB limitations due to built-in RAM on certain components.

In short, this behavior is normal and is a limitation of the motherboard which has a total of 4GB of available “address space”. Physical RAM and all PCI/PCIe hardware devices require a portion of this address space. When the amount of installed RAM nears the total capacity of the system, a certain amount of the installed RAM may be reserved for address space for hardware devices. However, how much RAM that is reserved for this purpose is defined by the motherboard. A UAD-1e card requires only 128MB, but 512MB has been allocated. The unused address space in this case is showing up as available to the video card. Unfortunately, this is just “the way it is” with 32-bit systems, and there is not really a workaround short of upgrading to a 64-bit system (and 64-bit version of Windows) with a different motherboard with a higher RAM capacity. (So as a side-note, this is the primary appeal of 64-bit systems, but in reality, for the current needs of the DAW user and with the advent of advanced disk-streaming technology, over 3GB of RAM is generally rather excessive for even the most demanding projects.)

Note that similar behavior will occur by installing any other PCI/PCIe devices as well (depending on the amount of address space each device requires). Also note that Windows Vista 32-bit faces the same limitations as XP. Only a 64-bit OS running on a 64-bit system has a higher address space limit.

Because physical RAM is currently over-allocated for address space on this system, if additional UAD cards are added, it should not require any additional RAM and 2.5GB will still be available to Windows. We happen to have the same A8N system here with 3 UAD-1e cards, 2 PCI sound cards and 3GB of RAM installed, and 2.5GB is still available to Windows.

Here is another article which goes into more detail: http://h20331.www2.hp.com/Hpsub/downloads/RAM_Allocation_w-WinXP_HP_MWP_x64.pdf

If your system has under 3.5 GB of TOTAL system RAM, then this is not your issue. please contact Tech Support for more details.

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