Actually, I have two desktops that I connect do my USRP2 (rev. 4, sn 940). One of them runs a 3 months old git code. The other runs a 2 weeks old code. I simplified my GRC model, transmitting only a 400hz tone with the following sample rate: Signal source (44.1k) -> Decimation (220.5m) -> UHD sink (200k). This setup runs fine in the "old" box, while i got a LOT of glitches and underflows in the new boxes. My fc is around 460MHz (GMRS frequencies), and when I say "glitches", I mean the noises I listen on my off-the-shelf transceiver. Although the hardware config is PRETTY different, between the two desktops, I don't believe this should be a problem. Anyway, I can get in details, if needed. Thanks in advance for any help, -- Thiago Augusto V. Lima Computer Engineer Networking and Telecommunications Research Group - GPRT (www.gprt.ufpe.br)