What is so good about SoundStorm?
The best place to start is discussing exactly what is so good about SoundStorm and why it should be considered the benchmark for computer audio. In an ideal world, the standards the SoundStorm produce should be just that, the standard - and then we should be seeing improvements over those base standards much more often than we do at the moment.
First and foremost, the beauty of the nVidia SoundStorm APU is that it is capable of encoding Dolby Digital 5.1 on the fly via hardware acceleration and not software (CPU). This means that in any games you play and as long as you are using optical or digital coaxial cable with your surround sound speakers (anything above 2.1 channels), the hardware APU will do the intensive job of reproducing the sound from the game to Dolby Digital 5.1 or AC-3 so you get proper positional surround sound.
No other computer sound solution on the market is capable of doing this - Creative can do this with their EAX positional surround sound via enhancing the signal along analog cables (and others can do the same type of thing with Microsoft DirectSound 3D and less so A3D these days) but it will only work in games which support EAX (and DirectSound 3D via DirectX and A3D) and it's not as good as Dolby Digital in terms of true cinematic realistic positional sound. Onboard sound solutions utilizing their digital SPDIF output (whether it be optical or coaxial, depending on what the manufacturer chooses to go for) can only output to the front two speakers as without an encoded 5.1 signal from the computer end beforehand, what is being sent through your digital optical/coax cable is limited to stereo (two channels) of sound... so you can kiss your surround sound in games goodbye. The only way you can achieve proper positional surround sound in gaming with all other sound solutions on the market apart from the mighty SoundStorm is to utilize their analogue outputs (centre/sub, front, & rear jacks) but then it is not digital so you don't get the true to life effects of proper digital.
Gaming companies could (in theory) implement a feature within their titles for RAW Dolby Digital 5.1 to be outputted as you play but for all sound solutions that don't have real-time hardware Dolby Digital encoding capabilities, it means your CPU would be taking a massive hit, making the game run like a dog. The beauty of SoundStorm is that it takes the hit off your CPU with the encoding on the fly and does it with its own APU in isolated hardware. Some brand new AC'97 2.3 audio codec's are said to be able to provide Dolby Digital encoding capabilities but it is done via software which means your CPU does all the work and the performance hit of performing such an intensive task would be bad and we aren't even sure if it will be on the fly like SoundStorm.
The only time other sound solutions that are able to play back a pure DTS or Dolby Digital 5.1 signal is when it is already in RAW format at the computer end - like when you play a DVD with PowerDVD. This software has an option in the settings to allow your audio to be outputted in a RAW untouched format called "SPDIF". It's merely a pass-through of untouched audio content on the DVD. The amplifier gets the signal that way, and decodes it by itself, which is exactly the same principle as that of a standalone DVD player connected to your amplifier in a home entertainment setup.
The final point about why the SoundStorm is so good is the fact that it does all its audio processing via its own hardware controller which is a more expensive design. Cheap onboard solutions from companies such as Cmedia and Realtek rely on the CPU to take care of all the audio processing tasks. Since valuable CPU cycles are being used up, your overall frames per second will be reduced. When you play games such as Battlefield Vietnam (which is one of the most impressive games I have played as far as sound goes) you really notice the drop in frames per second as the cheaper and inferior sound solutions just can't stand up to the pressure with the amount of sounds being processed. As you will soon see in our benchmark results, we noticed almost a 60% drop in performance with the cheap Cmedia onboard compared to the best performer.
The below table is from this nVidia technical brief PDF which you can download here which goes into detail about the SoundStorm APU.
Now we've covered the key points why SoundStorm is so good, we are ready to get into the testing notes and then benchmarks.
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