With DPC latency checker I can have values more than acceptable (around 80us) and, as written above, I used version 8.5 of Sonar LE, a really good daw to just be an OEM product (.Cakewalk beats all, there little to do).

The computer I used for this test is self-assembled one with a cheap Sapphire motherboard, AMD 740G, AMD Athlon II X2 250 and 4 GB of RAM, Windows 7 (without Service Pack 1) and with only the drivers included in Windows disk. From the audio track in Sonar LE 8.5, I chose the C03U as input and Delta AP1/2 as output, put the track on record and everything just got better! I also enabled monitoring on the track and, with a buffer adjusted to 160 (in asio4all panel) I can get a decent latency, I also set the recording to work with 24 bit in Sonar and I have to say that problems did not, the recording quality is more than satisfactory for a microphone for about $ 100.

Once installed ASIO4ALL drivers, after a few tries, I found that this configuration works very well: in Asio4all panel I enabled the voices Delta AP1/2 and put other off, and I also activated the Samson C03U. Reading various posts in other forums of hard disk recording, I've seen others use this mic with asio4all and then I decided to gave a chance too. So: I have in my computer, as main soundcard, an M-Audio Delta, which has its own Asio drivers, and it works perfectly. I think USB is a more versatile solution, especially because I can connect it directly to the notebook without having to carry even a sound card. I based my experience on the beautiful guide written by Fog and I decided to buy the C03U because i needed a relatively cheap microphone but with all the features that I could afford to use it for both voice and, above all, with the acoustic guitar. I would like to share with you my experience with the Samson C03U USB microphone, and the driver ASIO4ALL. Samson C03U with Asio4All: my personal experience

Samson mic drivers