Several Performance Upgrades Made to the Latest Versions of SDR#

Recently the popular SDR# (SDRSharp) software has had several improvements made to it (changelog). One of the most noticeable improvements is a decent reduction in the amount of CPU usage required by the software. We tested the new version on an i7 CPU and compared it against an older version using an Airspy. We saw 12% CPU usage on the older version and 7% on the newer version. With the RTL-SDR the older version showed 5% CPU usage which reduced to 3% on the newer version. Using an older i5 PC resulted in even larger improvements, going from about 35% CPU on the older version down to 25% or lower usage on the new version with the Airspy. The improvements are especially noticeable when decimation is used with the Airspy. These performance updates may help users on older PC’s and tablets run the software, or help users who run many programs at one time. The SDR# author is also testing out a 64 bit version of SDR#, which may be released in the future.

Recent versions over the past few months have also made improvements to the included noise blanker plugins and they have also added a default band plan plugin which shows the various frequency bands visually on the FFT spectrum.

Showing the very low CPU usage obtainable with the latest SDR# versions.
Showing the very low CPU usage obtainable with the latest SDR# versions.
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Just installed and I am TRULY impressed! Did a clean install and started over. I use it for FM radio and scanning mainly and this new version is fantastic. Takes a little time tweaking it but well worth the time. With my home brew dipole, I receive signals from 70 miles away. Now if I could only convince someone to do a plugin to allow the FM radio stations to set the gain for each station. Not that it isn’t great already but I’ve found some FM stations work better with different gain settings. THANK YOU for some outstanding software!!!!


Just downloaded the latest version described above and even though I’m using an dongle and up-converter, really do like the fact that the popular bands such as CB, SW, Air, Ham bands are identified at the bottom of the spectrum, and want to thank those folks at Airspy for all the enhancements.

The spectrum analyzer looks dandy but will have to eventually get an Airspy, and from what has been documented about it, looks like one of the best SDRs for the price.

One thing I did was to copy the frequency XML file from my older version over to the newer version’s directory so that all my stored memories would carry over.


I run SDR# on a Pentium4, 3Ghz Ram 2Gb. I did not notice any difference in CPU usage between v1444 and v1466; i tuned a FM station and in both cases they use 35% Ram and 100% CPU. In both cases CPU starts from 75% and reach 100% in about 40sec.


I tried to tune to a continuous digital signal on 447 Mhz in NFM mode, i kept the same settings for agc, filter bandwidth etc.
v.1444 ram 31% CPU oscillating between 50% and 60%
v.1466 ram 31% CPU oscillating between 60% and 70%
as far as i can see cpu usage is higher, not lower


Try the current version which is r1474.


v.1474 is much better.
With FM Broadcast:
v.1466 ram 36% CPU oscillating between 95% and 100% audio was skipping
v.1474 ram 36% CPU oscillating between 85% and 95% audio was continuous
With NFM digital signal:
v.1466 ram 36% CPU oscillating between 37% and 45%
v.1474 ram 36% CPU oscillating between 30% and 40%

The tests were made at 1.4 MSPS with SDR# reduced to icon otherwise the cpu usage increases and becomes difficolt to compare the values.


lower CPU usage might be good…but i can no longer hear any AM demod…i can see the signal on the waterfall..but all i get out is noise with very faint voices both on AM broadcast band with direct sampling, and Airband with quadrature sampling….SSB, CW and FM etc work fine!


The lower cpu usage is true ! The previous version of SDRSharp – wich running under win7/32bit an old Asus Eeepc-900 2g ram and RTL dongle – not running smoothly. I not seen the newer version changelogs, only download and install the eeepc. And not clicking, not popping, running perfectly but this machine (eeepc900) really slow. Apsolutely satisfy.