ASUS Xonar DX 7.1 PCI-E Sound Card
Through Asus cropping the size of the card in half it comes as no surprise that the majority of the connectivity is on the back of the card. A personal frustration of mine is that high end soundcards tend to have the actual fitting instructions engraved on the socket. While this is fine in a good lighting environment or the actual sockets are coloured it can be a little pain staking swapping out cables in dim light with gold plated connectors giving no clue as to what goes where. While I don’t expect the led lights of its forbear an optional coloured template/sticker would be a welcome addition for those of us who don’t possess night vision!
For those out there who prefer digital over analogue connections, the DX’s S/PDIF output is shared with its analogue mic and line input ports. You may also notice that the card is left wanting a digital S/PDIF input port although a 4pin auxiliary connector is provided should you wish to use it.
Upon closer inspection you will notice that the card is PCIex1 which will restrict itself to owners of later motherboards, it does however offer future proofing in return as motherboard manufacturers appear to be slowly phasing out the PCI standard in favour of the smaller standards available today. It’s also nice to actually make use of PCI-e x1 slots for change! Whether an express port’s bandwidth is actually utilised is doubtful however it is welcome and certainly adds to the appeal of the card. The card also requires the use of a floppy power connector which despite its small size just goes to show how powerful this card actually is. With the extra power going through the card, I was initially worried as to the heat that would inevitably be produced but my worries were unfounded as the card is no warmer than a regular card twice its size and certainly does not require the use of additional heat sinks or cooling despite its numerous solid capacitors and Vrms.
A notable difference between the DX and the more expensive DX2 is the addition of front panel audio headers which is a real bonus considering it is omitted in the more expensive version, the DX2.
Here we see the heart of the DX, the AV100 processing unit. Don’t be fooled into thinking this is anything other than C-media’s Oxygen HD audio chip though, not that it’s to its detriment. The AV100 is rumoured to be a ‘speed-binned’ AV200 processor which is also used in the DX2. As the Oxygen – sorry – AV100 was not designed to use PCIe there is also another chip onboard from PLX which Asus have utilised as a bridging chip enabling the card to use the PCIe as standard rather than the bandwidth limiting PCI interface.
Now here is something worth mentioning so listen up: Users of Nvidia’s latest 790i based motherboards have experienced difficulty in getting this card to work in Vista due to this bridging chip which seems to confuse the Nvidia chipset. I didn’t have an Nvidia based motherboard on which to neither confirm nor deny this but there are simply too many reports to ignore and not include this info in the review. The good news however is that NVidia are aware of this issue and are working on a new BIOS which will hopefully solve the PCI-PCIe bridging problem.