<p>Here is a benchmark comparing sparse matrix multiplication performance:</p>

<p><a href="http://uk.arxiv.org/abs/1302.1078" rel="nofollow">http://uk.arxiv.org/abs/1302.1078</a></p>

<p>It partly answers my question, but I would rather see more than one algorithm, and I would like to see how portable OpenCL performance is, I will still accept any answers which can provide that information.</p>
Benchmarks comparing Intel Xeon Phi and Nvidia Tesla K20
<p>To my surprise, I cannot find a comparison of these products using open source OpenCL benchmark suites, such as <a href="https://www.cs.virginia.edu/~skadron/wiki/rodinia/index.php/Main_Page" rel="nofollow">rodinia</a> and <a href="https://github.com/spaffy/shoc/wiki" rel="nofollow">SHOC</a>. Such a comparison could be more interesting than comparisons of theoretical peak performance, or of performance in simple matrix multiplication kernels, which I have been able to find.</p>

<p>Does anyone know where such results might be available? Failing that, do any stack overflow users have access to one or both products, and the time and inclination to run the benchmarks and share the results? Results for any of the versions of either card would be interesting.</p>